Palermo: The Duomo

Cathedral of Palermo.

Opinions about the cathedral of Palermo are quite divided. Some people think that the building is magnificent, and that the mixture of architectural styles presents us with an intriguing summary of the various phases in Sicilian history. Others, however, believe that the cathedral is simply hideous and lament what later architects have done to the original Norman-Sicilian edifice. The eminent historian of Norman Sicily John Julius Norwich can be counted among the detractors. As early as 1970 he called the cathedral of Palermo a “sad travesty”.[1] I personally think that goes too far. Admittedly, not every architectural intervention can be called a success, but the building still has a lot to offer, ranging from the tomb of one of the greatest monarchs of the Middle Ages to the crown of his wife. The cathedral itself can be visited for free. Those who also want to see the royal tombs, the roof terraces, the crypt and the treasury will have to buy a ticket.

Early history

According to tradition Palermo has had a bishop since the second century. In the middle of the fifth century a certain Mamilianus held the office. Together with a number of others he was taken prisoner by invading Vandals and deported to North Africa. Via Sardinia he ended up on the islands of Montecristo and Giglio, where he died. As a bishop, Mamilianus must have had his own cathedral, but as far as we know nothing remains of this building. The history of the cathedral of Palermo therefore starts during the pontificate of Pope Gregorius the Great (590-604). The cathedral was said to have been built when a certain John was archbishop of Palermo and to have been completed in 604. The building was dedicated to the Virgin Mary and some historians believe that the crypt of the current cathedral is a remnant of this building (although other historians have refuted this position). Another possible remnant of the original cathedral is the strange little building that we find to the north of the cathedral and that is known as the Cappella dell’Incoronata.

The cathedral seen from the Museo Diocesano.

Text from Sura 7 of the Quran.

In 831 the Muslim Aghlabids from North Africa captured Palermo. The cathedral of the city was taken from the Christians, most of whom were, by the way, Greek-Orthodox rather than Catholics. In other words, they aligned with the Patriarch of Constantinople rather than the Bishop of Rome (i.e. the Pope). The former cathedral was converted into a mosque, one of the 300 mosques[2] that were said to have stood in Balarm (the Arabic name of Palermo). The building was known as the Gami, a name that no doubt derives from Arabic Jami Masjid, a reference to the Great Mosque of the city where Friday prayers were held (cf. Turkish camii and Greek τζαμί). An inscription on one of the columns (the one on the far left) of the portico on the south side of the cathedral serves as a reminder that the building was once an Islamic house of prayer. According to this source the inscription is a verse from Sura 7 of the Quran. We may ask ourselves why the text was never chiselled away. Was it out of respect for the Holy Book of another religion or, quite the opposite, to demonstrate that Christianity had ultimately triumphed over Islam?

In the meantime, the conversion of the cathedral into a mosque had certain consequences for the Christians of Palermo. They were allowed to practice their religion, but were subject to certain restrictions and were moreover required to pay the jizya, a tax for non-Muslims. The Orthodox archbishop left the city and, together with his court, settled on the Monte Caputo, where the small chapel of Hagia Kyriake became the new “cathedral”. Later the town of Monreale was founded on the aforementioned mountain, and in the twelfth century King William II of Sicily (1166-1189) cleverly used the status of the chapel to grant the immense church that he built there between 1174 and 1189 the rank of a cathedral. More information about the cathedral of Monreale and its relationship with the cathedral of Palermo can be found below.

On 10 January 1072 the Normans, led by Robert Guiscard (1015-1085) and his younger brother Roger de Hauteville (1031-1101), took Palermo. The Normans were Catholic or Latin Christians, but they were more than happy to cede the Gami mosque to the Greek-Orthodox archbishop Nicodemus, who reconsecrated the building as a Christian cathedral and then held a thanksgiving service according to the Byzantine rite. Nicodemus was the last Greek-Orthodox archbishop; his successors were all Catholics. Ever more Catholics from Southern Italy settled on Sicily, and so Catholic influence on the island increased dramatically over the years. While Roger de Hauteville only bore the title of Great Count of Sicily, his son Roger II thought bigger. In 1127-1128 he annexed Southern Italy (previously held by his cousin William of Apulia), and in 1130 he had himself anointed King of Sicily in the cathedral of Palermo by a legate of Antipope Anacletus II. The ceremony presumably took place in the aforementioned Cappella dell’Incoronata, remodelled by Roger II and subsequently used for the coronation of the other Norman-Sicilian kings.

Robert Guiscard and Roger de Hauteville grant the cathedral of Palermo to Archbishop Nicodemus. Fresco in the apse by Mariano Rossi, painted in 1803.

The aforementioned King William II of Sicily, a grandson of Roger II, had a strained relationship with the archbishop of Palermo, Walter of the Mill. Walter was an Englishman who had started his career as a tutor of William and his brothers when these were still children. He had next been appointed archdeacon of Cefalù and canon of the Cappella Palatina in Palermo. In 1168 he was appointed archbishop of Palermo. In that year the favourite of William’s mother Margaret of Navarre, her cousin Stephen du Perche, was forced to step down as archbishop. Walter then held the office until his death in early 1191, and at an unspecified moment in the 1170s he began rebuilding the cathedral. His rebuilding project is often seen as part of the struggle between Walter and William, and between Palermo and Monreale. William supposedly started the construction of the cathedral of Monreale (some 6-7 kilometres outside Palermo) to restrict the power of Archbishop Walter. The latter indeed lost several parishes to the new archdiocese. In response Walter was said to have launched the rebuilding of his own cathedral.

Side view of the cathedral.

Rear of the cathedral.

The problem is that we do not know when exactly Walter started his project. It may have been around 1170 (which makes it unlikely that it was a reaction to King William’s project), but perhaps it was as late as 1179.[3] It cannot be ruled out that the archbishop had other motives as well for wanting to rebuild his cathedral. The cathedral was several centuries old, perhaps in need of large-scale maintenance and moreover more or less unchanged since the building had been taken from the Muslims. This was the moment to grant Palermo a magnificent new cathedral in the Norman-Sicilian style. On 6 April 1185 the new cathedral was consecrated by the archbishop. True to the Norman style the building had a nave and aisles, with a slightly raised choir. Flying buttresses across the street – now the Via Matteo Bonello – connected the building with the bell-tower, which had been built against the archiepiscopal palace. Unfortunately we have very little information about the interior of the new cathedral. If it was embellished with frescoes and mosaics, then nothing of these decorations has survived. The original wooden roof construction was largely replaced during later renovations. The four conspicuous corner towers of the cathedral were only added in the fourteenth century.

Later history

The cathedral of Walter of the Mill has been remodelled quite a few times over the course of the centuries. The most original part of the building is perhaps the rear with its three apses. These can best be viewed from the Piazza Sett’Angeli. The beautiful geometric patterns on the apses strongly resemble those of the cathedral of Monreale. The merlons of the building are also original Norman-Sicilian elements. The large square in front of the cathedral (a former cemetery) was completed in 1195. The balustrade surrounding it was added in the sixteenth century and provided with statues of saints in the next century. In the eighteenth century the balustrade was replaced with a new one. That is the balustrade we see today.

Madonna and Child with angels.

Visitors usually enter the cathedral through a portal on the south side of the building that was added between 1423 and 1426. The portal is an example of the Catalan-Gothic style and it is a work by the architect Antonio (or Antonino) Gambara (died ca. 1442). The portal was built on the occasion of the coronation of King Alfonso V of Aragon, who was King of Sicily between 1416 and 1458 and who was nicknamed “the Magnanimous”. Moreover, Alfonso was King of Naples between 1442 and 1458 (as Alfonso I), which meant that for the first time since the thirteenth century the island and Southern Italy were ruled by one and the same monarch. A thirteenth-century mosaic of the Madonna and Child flanked by angels was inserted into the top part of the portal. A fitting decoration, as the cathedral is dedicated to the Virgin Mary (and her Assumption). The doors in the portal were made by Francesco Miranda and installed in 1432.

A few decades later the large portico on the south side of the cathedral was built, which is also an example of the Catalan-Gothic style. The portico has a beautiful tympanum, with a central scene of God the Father in the middle of an Annunciation. God is depicted here as a pope, with a tiara on his head and sitting on a throne. Below the tympanum we see two dozen smaller figures, all of them saints, apostles, evangelists or prophets. The cathedral, by the way, also has an official main entrance, on the west side, in the Via Matteo Bonello. It looks like it is seldom used. This entrance consists of a fourteenth-century Gothic portal with modern bronze doors. The doors are the work of Filippo Sgarlata (1901-1979), who made them in 1961. On the north side, in the Via Incoronazione, is another entrance. The original portico on this side was made by the brothers Fazio (1520-1567) and Vincenzo Gagini (1527-1595), both sons of the famous Antonello Gagini (1478-1536). The portico was remodelled in the eighteenth century, as part of a larger project that completely altered the appearance of the cathedral.

Portico on the south side.

Tympanum; God the Father in the middle of an Annunciation.

The eighteenth century initially saw a couple of fairly modest restorations. The bell-tower for instance had to be rebuilt after an earthquake in 1726, and in 1767 the architect Ferdinando Fuga (1699-1782) executed a restoration aimed at conserving the building. Fuga also planned a much bigger renovation that was ultimately to be executed between 1781 and 1801. By the time the project was launched, the architect was already in his early eighties, and he would die in 1782. This means we should largely ascribe the renovation to Giuseppe Venanzio Marvuglia (1729-1814) from Palermo. Lord Norwich, already mentioned in the introduction to this post, was highly scathing about the result:

“[T]he crowning desecration, literally and figuratively, on the outside and within, took place in the eighteenth century when the Florentine architect Ferdinando Fuga clapped on a ludicrous and totally unrelated dome, hacked away the side walls to make fourteen chapels, removed the wooden roof and replaced it with inferior vaulting, then whitewashed the whole thing – the apse mosaics had already been torn down two centuries earlier – and baroqued it up beyond recognition. Today the kindest thing to do about Palermo Cathedral would be to ignore it – were it not for the Royal Tombs.”[4]

Statues by Antonello Gagini and sons in the cathedral.

While no one could rant so eloquently as the late Lord Norwich (he died in 2018), his criticism is not entirely fair. First of all, Fuga was ultimately hardly involved in the renovation, and it is up for debate whether Marvuglia and his associates stuck to Fuga’s plans. The replacement of the wooden roof constructions, in any case those in the aisles, had moreover already taken place in 1709 and the interior of the cathedral is Neoclassical rather than Baroque. And yet it cannot be denied that the eighteenth-century renovation has needlessly destroyed a lot. The best example of wanton destruction is the so-called tribuna by Antonello Gagini in the central apse. It consisted of three rows of saints, one above the other, forty in total and complemented by reliefs featuring the Assumption, the Risen Christ, God the Father and stories about the lives of the saints that were included. From 1510 until his death in 1536, Antonello Gagini worked on the tribuna. His sons continued the work until 1574, but at the end of the eighteenth century the whole construction was disassembled. The relief of God the Father in the conch of the apse (by Vincenzo Gagini) was lost altogether and most of the statues were placed outside between the merlons of the cathedral (which must have looked rather ridiculous). It was not until 1952 that the statues were relocated to the interior of the building.

The big renovation of 1781-1801 not just provided the cathedral with one large dome, but also with sixteen smaller domes, eight on every side. Each little dome has a colourful majolica roof. The large bell-tower got its present appearance in 1835, after it was heavily damaged by an earthquake in 1823. The Neogothic tower that we can admire today is a work by Emmanuele Palazzotto (1798-1872).

Interior of the cathedral.

Interior

The Neoclassical interior of the cathedral can hardly be considered beautiful, but it does have a number of interesting elements. Columns from the cathedral of Walter of the Mill have been incorporated into the large pillars that divide the building into a nave and two aisles. The statues from the tribuna of Antonello Gagini and his sons have been set up against these pillars (see the image above), and the Risen Christ has (again) been granted a spot in the central apse. This apse is now covered by a large fresco made in 1803 by the painter Mariano Rossi (1731-1807). We see how Robert Guiscard and Roger de Hauteville give the cathedral back to Archbishop Nicodemus (image above). Rossi also painted the Assumption of the Virgin on the barrel vault of the choir. On the left in the choir we see the royal throne and a Paschal candlestick. The two items are reconstructions, but original material was used to create them. The Cosmatesque decorations are beautiful. The text on the throne reads PRIMA SEDES CORONA REGIS ET REGNI CAPVT, or “first residence, crown of the King and capital of the Kingdom”, which are all references to the city of Palermo.

If you wander through the building, you will notice quite a few other nice works of art. I especially liked a holy water stoup by Domenico Gagini (ca. 1420-1492), Antonello’s father. Very important from a religious point of view is the chapel to the right of the choir, dedicated to Saint Rosalia. She is the most prominent patron saint of Palermo. In the twelfth century Rosalia left the city to live on the Monte Pellegrino as a hermit. Although she was venerated as a saint after her death in 1166 or 1170, it was not until the plague of 1624 that her cult really gained momentum. By that time Palermo already had a plethora of patron saints, but neither Olivia, nor Nympha, Agatha and Christina proved to be able to stop the terrible disease. Fortunately some two months after the outbreak of the plague Saint Rosalia’s body was rediscovered and – coincidence or not – it was right at that moment that the curve of infections began to flatten. Rosalia has been considered patron saint of the city ever since. Her chapel in the cathedral, where her relics are kept, was completed in 1635, but the wall reliefs by Valerio Villareale (1773-1854) date from 1818. In the square in front of the cathedral we find a statue of Santa Rosalia in the centre.

Piazzi’s meridian.

Lastly, what is special about the interior of the cathedral is the presence of a bronze meridian. It is the work of Giuseppe Piazzi (1746-1826), who was both a priest and a mathematician and astronomer. The meridian was placed in 1801 and marked the start of European time reckoning on Sicily. It strongly reminded me of a similar meridian in Rome, which is, however, almost a hundred years older.

Royal tombs

Visitors with tickets can admire four imposing royal tombs in the first two chapels on the right side. In the back on the left is the tomb of Roger II, King of Sicily between 1130 and 1154. He was, as was already mentioned above, the founder of the Norman-Sicilian kingdom, which also comprised all of Italy south of the river Garigliano. To the right of Roger’s tomb is that of his posthumous daughter Constance (1154-1198). She was married to Henry VI, Holy Roman Emperor, who because of his marriage to Constance also became King of Sicily (Roger’s grandson William II had died childless). Immediately after his coronation Henry VI turned out to be a merciless tyrant, so the Sicilians probably did not shed any tears when he died in 1197 at the tender age of 31. In spite of his tyranny, he was granted a beautiful porphyry sarcophagus that has now been placed in front of that of his wife. The last tomb, also made of porphyry and placed front left, is that of the son of Constance and Henry, Frederick II of Hohenstaufen. I have told the story of this larger than life character before, and will repeat it here almost verbatim.

Tomb of Emperor Henry VI. Behind it the tomb of his wife, Constance of Sicily.

Frederick was born on 26 December 1194 in the small town of Jesi in the Marche. His parents died when he was still very young, and after their deaths the new Pope Innocentius III (1198-1216) took care of the young orphan and became his guardian. Cencio Savelli – the future Pope Honorius III (1216-1227) – was appointed as the boy’s tutor. As a four-year-old, Frederick was already King of Sicily (after the death of his mother in 1198), but for the moment the position of Holy Roman Emperor eluded him. Henry VI was first succeeded by his brother Philip of Swabia and then by Otto of Brunswick. Frederick later successfully took up arms against the latter. When Otto – known to posterity as Otto IV – had been soundly defeated by the French at Bouvines, Frederick became the new King of the Romans. In 1220 he was crowned Holy Roman Emperor by his former tutor Pope Honorius III.

Frederick was undoubtedly one of the greatest monarchs of the thirteenth century, as is evidenced by his nickname stupor mundi, which is Latin for “astonishment of the world”. The Emperor was a great intellectual, who was very interested in science and was fluent in multiple languages, including Arabic. His proficiency in that language was hardly surprising. At the time Sicily was still home to a substantial minority of Arabic-speaking Muslims, the result of the Aghlabid conquest of 831 discussed above. The Norman conquest between 1061 and 1091 did not immediately end the influence of Islam on Sicily. Even in Frederick’s days, more than a century later, large groups of Muslims still inhabited the island. Frederick himself was of course a Catholic monarch, but his interest in Islam was genuine and he greatly admired the works of Islamic scholars. In an era of religious fanaticism and crusades, this gave him a bad reputation, especially with Pope Honorius’ successors. Frederick constantly found himself at odds with these gentlemen, Popes Gregorius IX (1227-1241) and Innocentius IV (1243-1254).

Tomb of Emperor Frederick II. Behind it the tomb of his grandfather, King Roger II.

As early as 1217 Frederick had promised Honorius to go on a crusade. The holy city of Jerusalem had been captured by the armies of the First Crusade in 1099, but in 1187 it had been retaken by the Muslims. Frederick made preparations for a campaign to recapture the city, but kept procrastinating his departure for Palestine. When he finally started his crusade in 1227, Honorius had already died. Moreover, Frederick himself was struck by a serious illness. Honorius’ successor Gregorius IX showed little sympathy and excommunicated the Emperor for breaking his promise, an act he repeated the next year when a recovered Frederick sailed to Jerusalem. In spite of these setbacks, Frederick continued his crusade and – still excommunicated – concluded a ten-year peace treaty with Sultan Al-Kamil of Cairo. The treaty stipulated that Jerusalem, Nazareth and Bethlehem were to be returned to the Christians. Not a single drop of blood had been shed. Frederick was crowned King of Jerusalem and the city would remain in Christian hands until 1244.

Although he had set foot in the holiest city of Christianity as an excommunicated man, Pope Gregorius undid Frederick’s excommunication, only to excommunicate him again in 1239. Gregorius passed away in 1241 and his successor Celestinus IV died after just 17 days on the throne of Saint Peter. Sinibaldo dei Fieschi – who was elected in 1243 and took the name of Innocentius IV – was then Frederick’s nemesis for the seven remaining years of the latter’s life. Frederick was almost immediately excommunicated again, and on 13 December 1250, about two weeks before his 56th birthday, the Emperor died of dysentery. He was laid to rest in a porphyry sarcophagus that was originally not intended for him, but for his grandfather Roger II. It had always been Roger’s fervent wish to find his final resting place in the cathedral of Cefalù, which he had built himself. It was there that two porphyry sarcophagi were placed, one as a tomb for the King, the other as an empty memorial for the Hauteville family. After his death in 1154, Roger’s wish was sadly ignored, and he was buried in the cathedral of his capital Palermo. The two sarcophagi remained in Cefalù for decades, but in 1215 Frederick had them taken to Palermo to be used for himself and his late father.

Tomb of Constance of Aragon, wife of Emperor Frederick II.

Little domes with majolica roofs.

In the right chapel we also find, on the wall, the tomb of Constance of Aragon, Frederick’s first wife. She had been born between 1179 and 1183, so she was much older than her husband (and she had already been married to the Hungarian king Imre). Constance died in 1222 in Catania and was laid to rest in the cathedral of Palermo in an ancient Roman sarcophagus. She had borne Frederick a son, Henry (1211-1242), who was elected King of the Romans, but ultimately rebelled against his father and spent his final years in captivity. Frederick was therefore succeeded by his son Conrad, born from his second marriage to Yolande of Brienne (1212-1228). In 1235 Frederick married for the third time, this time to Isabella of England (ca. 1214-1241), a sister of the English king Henry III. After Conrad’s death in 1254 the de facto ruler of Sicily was Manfred, Frederick’s favourite illegitimate son. As of 1258 Manfred began officially calling himself King of Sicily, but in 1266 he was defeated by the Frenchman Charles of Anjou, whose victory ushered in the Angevin era in Sicilian history (see Palermo: Santo Spirito and the Sicilian Vespers).

The roofs

A door in the counter-façade gives visitors access to a staircase that leads to the roofs of the cathedral. A kind of mezzanine then offers a nice view of the little domes of the right aisle. However, the view from the roof of the nave is much more spectacular. Look towards the west and you will see the former royal palace, the Palazzo dei Normanni. Then look across the square in front of the cathedral and admire the many domes of the Palermitan churches, with in the background the morning fog between the mountains surrounding Palermo. For the best view, look towards the north. There the mighty Monte Pellegrino rises, the mountain on which Saint Rosalia lived and where we find her seventeenth-century sanctuary (the castle on the mountain is the Castello Utveggio, built in 1934). Visitors also get a good view of the Teatro Politeama, which opened to the public in 1874, and can lastly walk around the dome designed and constructed by Fuga and Marvuglia.

The Palazzo dei Normanni, seen from the cathedral.

Skyline of Palermo.

View of the Monte Pellegrino. On the right the Teatro Politeama.

Crypt and treasury

The exact age of the crypt is debated. As was already mentioned, it may be a remnant of the 604 cathedral, but there are plenty of historians who date the crypt to the twelfth or even the fourteenth century. Irrespective of its age, the crypt is interesting because of the 23 sarcophagi that have been placed down here. According to an information panel 11 of these have always stood in the crypt, while the other 12 were placed here during the great renovation of 1781-1801. As with Constance of Aragon’s tomb, the tombs are often pagan Roman sarcophagi that have been adjusted to serve as the final resting places of the Christian dead.

Tomb of Archbishop Hugh.

Examples of Christian dead are, of course, in the first place the archbishops of Palermo. In the crypt we for instance find the sarcophagus of Archbishop Hugh, whose episcopate lasted from 1150 to 1161. Hugh’s sarcophagus is a clear example of a reused Roman sarcophagus, which still features the pagan deities Tiber (a personification of the river) and Ceres. Archbishop Walter of the Mill, responsible for rebuilding the cathedral in the twelfth century, was on the other hand laid to rest in a Norman sarcophagus. Unfortunately a large part of the decorations of this sarcophagus has been lost. And then there is the sarcophagus of Giovanni Paternò, archbishop from 1489 until his death in 1511. The sarcophagus itself dates from Antiquity, but the reclining effigy of the deceased obviously does not. Paternò’s name was chiselled into his pillow.

Tomb of Archbishop Walter of the Mill.

Tomb of Archbishop Giovanni Paternò.

Pietro Tagliavia d’Aragona, archbishop between 1544 and 1558, was also granted a Roman sarcophagus, but this one is from the early Christian era. In the centre we see a Christian cross with two pigeons and above it a wreath which once held the Greek letters chi and rho (XP), the first letters of the name of Christ. Considering the fact that there are twelve figures flanking the cross, it is hard not to think of the twelve apostles. In the crypt we once again stumble upon Frederick II when we study a sarcophagus that was made for his great-grandson Frederick of Antioch. Manfred was far from Frederick’s only illegitimate child. He also had another son, whose name was Frederick. Frederick’s son Conrad had five sons of his own. Two of these (Bartolomeo and Francesco) became archbishops of Palermo. It was no doubt their doing that their oldest brother, the aforementioned Frederick of Antioch, was interred in the crypt after his death in 1305. That the family was well respected, in spite of its bastard origins, is demonstrated by the fact that three of Conrad’s daughters married members of the Della Scala family from Verona.

Tomb of Archbishop Pietro Tagliavia d’Aragona.

Tomb of Frederick of Antioch.

Crown of Constance of Aragon.

The crypt gives access to the treasury, where the highlight must be the crown of Constance of Aragon. The beautiful object was made in the tiraz (textile workshop) of the royal palace and consists of gold and silver thread, pearls and other precious stones. The large red and black stone on the front side has a text in Arabic that can be translated as “Isa, son of Gibair, trusts in God”. Isa – the Arabic name of Jesus – may have been the name of the maker of the crown. The object is dated to 1220-1222. At the time Palermo was still culturally Arabic, but the tolerance that had been so characteristic of the Norman-Sicilian kingdom had unfortunately already been eroded. As a result, many Muslims had left the city and had started a guerilla war against the Christians in the rough and barren regions of Western Sicily. In 1222-1226 Frederick II was forced to act against the rebels, forcibly moving several thousands of them (perhaps as many as 15-20,000) to Lucera in Apulia. There the Muslim community survived for a few more decades.

Sources

Notes

[1] John Julius Norwich, The Kingdom in the Sun, p. 316.

[2] John Julius Norwich, The Normans in the South, p. 177.

[3] The year mentioned in Capitool travel guide Sicily (2019), p. 70 and The Kingdom in the Sun, p. 316.

[4] The Kingdom in the Sun, p. 363.

5 Comments:

  1. Pingback:Cefalù: The Duomo – – Corvinus –

  2. Pingback:Palermo: Palazzo Abatellis – – Corvinus –

  3. Pingback:Palermo: Santissima Trinità del Cancelliere (La Magione) – – Corvinus –

  4. Pingback:Palermo: La Zisa – – Corvinus –

  5. Pingback:The cathedral of Monreale (part 1): history and exterior – – Corvinus –

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.