Last week, we shared an essay by our president, Dr Eric Hewett, about medieval-style of mosaic known as Cosmatesque, which is used in VSI’s logo. This complex arrangement of geometric patterns was made possible largely because of the vast amounts of colored stone that the Romans brought to their capital in antiquity to decorate its buildings. The colors in our logo, purple and green, represent an Egyptian stone called porphyry and a Greek stone called serpentine, respectively. In those Roman churches that still preserve Cosmatesque mosaics, one can also easily find giallo antico (Italian for “old yellow”) from the deserts of ancient Numidia (in the modern states of Tunisia and Algeria), white and grey marbles from various places in Italy and Greece, and variegated stones from different parts of Asia Minor.

In the past, I often had occasion to bring students to churches in Rome with Cosmatesque floors. I made it a practice to find a place where the mosaic was particularly complex, and tell one of them, “Put your foot here,” and then say to the group, “Your classmate is currently standing on bits and pieces of Italy, Greece, northern Africa, Asia Minor, and Egypt; the breadth of the Roman Empire in a single footstep worth of mosaic.”

A section of Cosmatesque pavement in the floor of the Basilica of Santa Maria Maggiore in Rome.

Since Rome itself had by far the highest concentration of such materials, Cosmatesque mosaics were relatively easy to make there, since the material was free for the taking from the ruins of ancient buildings. Outside Lazio, the central Italian region of which Rome is now the capital, they are rather less common, because it was costly to ship the necessary materials elsewhere. The style was very fashionable in Venice for a time, and is seen there most prominently on the floor of the Basilica of St Mark; fairly small panels of it can be found on the outside of several Venetian palaces. Other examples can be found in the baptistery of Pisa Cathedral, and the Capella Palatina (palace chapel) in Palermo. Outside of Italy, there is only one medieval example, the floor of the sanctuary of Westminster Abbey in London, which was installed at spectacular expense by Italian craftsmen at the behest of King Henry III, beginning in 1268.

Conservation work on the Cosmatesque floor of Westminster Abbey. (Image from Wikimedia Commons by Christine Smith; CC BY-SA 3.0)

In Rome, the style flourished especially in the twelfth and thirteenth centuries, and declined, along with the rest of the city, during the 14th century, when the Popes made the French city of Avignon their more-or-less permanent place of residence. But it flourished again, along with the rest of the city, once Pope Martin V (1417-31) returned the papacy to full-time residence in Rome in the early years of the 15th century. One of the largest surviving examples is in the central nave of the Lateran Basilica, the cathedral of Rome, which he had installed as part of a general rebuilding project. Later on in that century, it was used on the floor of the Sistine Chapel, constructed under Pope Sixtus IV (1471-84), and at the beginning of the 16th century, by his nephew Julius II (1503-13) in the papal apartments now known as the rooms of Raphael, who did the famous paintings on the walls.

However, these projects at the Vatican would prove to be the medium’s swansong, partly just because styles always change, and certainly changed with unusual rapidity and thoroughness in the Italian Renaissance. More importantly, the Protestant Reformation would begin under Julius’ successor, Pope Leo X Medici, and lead ultimately to the Council of Trent and the Counter-Reformation. This great reform movement within the Church was very much concerned with the use of churches, and the artworks inside them, as tools for the education of the faithful, and the Cosmatesque style came to be seen as simply too busy and too purely decorative.

The Lateran Basilica provides an excellent example of this shift. More than 200 years after Pope Martin’s time, Innocent X entrusted the project of a radical renovation to the architect Francesco Borromini, who was, however, forbidden from getting rid of anything that was still structurally viable. This meant mostly that Borromini could do what he wanted in the church’s side aisles, but had to leave the floor and ceiling of the central nave alone. In those parts of the church where he could do as he pleased stylistically, the Cosmatesque pavement was completely removed, and replaced with a simple geometric pattern in muted colors.

In the first image below, the central nave of the Lateran Basilica, with the Cosmatesque pavement of the 1420s; in the second image, the south aisle, with the new pavement by Borromini. (Both photographs courtesy of Fr Lawrence Lew OP.)