The first section of the Church was built in the Gothic Style between 1502 and 1519. The church consists of a single nave with seven chapels on either side which are decorated with many famous frescoes. Of these the most famous is undoubtedly the 'Deposizione' (Descent from the cross) by Daniele da Volterra. At first, this was positioned over the altar of the Chapel Orsini. Sometime afterwards it was moved, out of context, to its current position in the Chapel Bonfili.
The 'Deposizione' is one of the masterpieces of 'Mannerism', a period of European art which developed at the end of the Renaissance. Mannerism rejects the balance and harmony of classical art, focusing instead on the contrast between the different elements. The 'Deposition' was originally part of a series of frescoes painted by Daniele da Volterra just before the middle of the 16th century. Unfortunately, most of the others were lost.
The oldest part of the church is covered with pointed or 'ogival' arches. These arches are a specific feature of Gothic architecture used to support a Gothic vault.
Compared to the classic arches with their rounded shape, ogival arches give the feeling of greater verticality to the building.
Two thirds of the way up to the nave stands a bronze gate.
Of the fourteen chapels, several deserve special mention:
Starting on the right side of the aisle, the first chapel is that of St. John the Baptist which dates back to 1573. The frescoes of this chapel were painted by Giovanni Battista Naldini.
The third chapel is that of the Assumption and the frescoes here are by Daniele da Volterra.
The fourth chapel, the Orsini chapel known as the chapel of the Holy Sepulchre, contains frescoes dating back to the sixteenth century and were created by Paris Nogari. The altarpiece currently behind the altar has replaced the original which was by Pallière.
The fifth chapel is of the Nativity and its frescoes were painted by an anonymous artist. The complex of frescoes which decorate the chapel are centred around the Nativity, to the right is The Adoration of the Magi, and to the left The Circumcision. In the vault there is a fresco illustrating the prophets.
The sixth chapel, The Ascension, is characterised by frescoes from the school of Perugino. Peter Cristoforo Vannucci, known as Pietro Perugino or just Perugino, was an Umbrian painter, born in town of Pieve in 1448 and who died in Fortignano in 1523. He was was the proprietor of two studios, one in Florence and the other in Perugia and he was famous as the teacher of Raffaello.
His style is distinguished by its purity of form, the serenity of its composition, elegant design and good definition and the rich colour of light laid out with fine modulations of light and shade. The figures are typically freed from earthly characteristics and are made to look angelic and soft. However, he remained locked into the fifteenth century mindset where the figures that are merged in composition, are first designed and studied separately and then juxtaposed side by side as omnipresent flying angels. In spite of these limitations, he influenced an entire era.
On the left side of the aisle the first chapel is The Pietà and the frescoes here were painted by Cesare Nebbia. This chapel also contains sculptures by Achtermann Wilhem who moved to Italy in 1839 and remained there until his death. He created much of his work in italy and some of the best examples are conserved in the Chiesa Trinità dei Monti.
The third chapel on the left, Mary Magdalene, was originally decorated with frescoes by G Roman and G. F. Perini, both of whom were successful disciples of Raffaello. subsequently, the task of completing these frescoes was entrusted to Perin del Vaga and his work aroused much admireation. Unfortunately, the collapse of the roof in the nineteenth century compromised most of the works of art. Some of the remaining works are now held by the National Gallery and the Victoria & Albert Museum in London.
The left side ends with the Chapel of the Virgin which was also painted by Perin del Vaga. The chancel is raised and the centre of the alter is dominated by a colonnade.