A Guide to
​St Peter's Basilica

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Mosaics

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Dome Mosaics, Gregorian Chapel

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St Peter's Basilica is home to a huge number of mosaics; 10,000 square metres in total.

The first mosaics were created at the behest of Pope Gregory XIII (r. 1572-85), who entrusted the painter Girolamo Muziano (1532-92) with the design of the mosaic decoration of the dome of the Gregorian Chapel, which was the first area of the new St Peter's to be liturgically usable. Following its success, it was decided to extend this type of decoration to Michelangelo's dome (1603-1612) and then to all the domes of the Basilica.

Ground Plan of St Peter's Basilica

In addition to the large cupola, there are ten smaller cupolas. Four are round and are situated over the corner chapels in the main body of the church. Six are oval and were erected by Carlo Maderno over the two aisles. 

​While the domes were being decorated, work began on the reproduction in mosaic of the basilica's altarpieces, which were deteriorating on account of the humidity. 

​A special workshop, the Studio del Mosaico, was founded in 1727 by Pope Benedict XIII (r. 1724-30). Almost 300 years later, the workshop is still busy restoring old mosaics and manufacturing new ones. 

Dome Mosaics (Top Left Bay)

Left Aisle:

Dome Mosaics (First Bay, Left Aisle)

The first chapel off the left aisle is the Baptistery and accordingly the mosaics in the dome of the first bay deal with the subject of baptism. The mosaics were designed by the painter Francesco Trevisani (1656-1746) and were executed under the supervision of Pier Paolo Cristofari, who was the first director of the Studio del Mosaico. 

Dome Mosaics (Second Bay, Left Aisle)

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Dome Mosaics (Third Bay, Left Aisle)

Right Aisle: 

Dome Mosaics (First Bay, Right Aisle)

Dome Mosaics (Second Bay, Right Aisle)

Dome Mosaics (Third Bay, Right Aisle)

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