The Sistine Chapel is named after his commissioner, Sixtus IV della Rovere (1471-1484), who decided to have a large room built where the “Cappella Magna” once stood. The “Cappella Magna” was a mediaeval fortified hall that the Papal Court used for assemblies. At that time, it was made up of about 200 members: a college of 20 cardinals, representatives of religious orders and important families, a choir, and a large number of laymen and servants. The Sistine construction was also to be a defensive structure, warding off both the Medici family, because of the continuous tension between the rulers of Florence and the Pope, and Muhammad II’s Turks, who at that time were threatening the western coast of Italy. Its construction started in 1475, during the Jubilee Year proclaimed by Sixtus IV, and ended in 1483, when on August 15th the Pope solemnly inaugurated the new Chapel dedicated to Our Lady of the Assumption. The project, designed by Baccio Pontelli, included the use of a third of the height of the existing mediaeval walls.
According to some scholars, the dimensions of the hall (40.23 metres in length, 13.40 metres in width and 20.70 metres in height) are copied from Solomon’s great temple in Jerusalem, which was destroyed by the Romans in 70 A.D.
The main entrance to the Chapel, located opposite the small entrance used today, is preceded by the imposing Sala Regia built for papal audiences. Arched windows light the chapel, while lunettes and triangular webs join the ceiling’s barrel vault with the side walls. A choir once used the stalls on the right, while the Papal Court sat on the stone benches along three sides of the hall, excluding the altar side. An elegant 15th century balustrade surmounted by candelabra divides the area destined to the clergy from the area used by the public; at the end of the 16th century the balustrade was pushed back to make the former area larger. The splendid 15th century mosaic floor was copied from mediaeval models and is completely original.
After the architectural structure was completed in 1481, Sixtus IV summoned various Florentine painters to work in the chapel, including Botticelli, Ghirlandaio, Cosimo Rosselli, Signorelli and Umbrian artists such as Perugino and Pinturicchio.