Italian Renaissance painting an impressive Classical fresco of the sea nymph, Galatea, outstanding portraits with two popes and a famous writer among them, and, while Michelangelo was painting the Sistine Chapel ceiling, a series of wall frescoes in the Vatican chambers nearby, of which "the School of Athens" (1509-11) in the Stanza della Segnaturais is uniquely significant. This fresco depicts a meeting of all the most learned ancient Athenians, gathered in a grand classical setting around the central figure of Plato, whom Raphael has famously modelled upon Leonardo da Vinci. The brooding figure of Heraclitus who sits by a large block of stone,
Sistine Chapel congregations. These included the Christmas Day and Easter masses, at which the Pope himself was the celebrant. The other 27 masses could be held in a smaller, less public space, for which the "Cappella Maggiore" was used before it was rebuilt on the same site as the Sistine Chapel. The "Cappella Maggiore" derived its name, the Greater Chapel, from the fact that there was another chapel also in use by the Pope and his retinue for daily worship. At the time of Pope Sixtus IV, this was the Chapel of Pope Nicholas V, which had been decorated by Fra Angelico.