In 1656, Pietro da Cortona (1596-1669) was commissioned by Pope Alexander VII to enlarge the tiny Piazza della Pace in front of the 15th-century church of Santa Maria (to accommodate the carriages of its wealthy parishioners). His architectural solution was to design a new church facade complete with semicircular portico, demolish a few buildings here and there to create a more spacious approach to the church, add arches to give architectural unity to the piazza, and then complete it with a series of bijou-size palaces. The result was one of Rome's most delightful little architectural stage sets. Within the church are two great Renaissance treasures: Raphael's fresco of the Sibyls above the first altar on your right, and the fine decorations of the Cesi Chapel, second on the right, designed in the mid-16th century by Sangallo. Behind the church proper is its cloister, designed by Bramante (architect of St. Peter's) as the very first expression of High Renaissance style in Rome. The church is usually closed but if you take the alleylike Vicolo along the left-hand side of the church and ring the bell at the first entryway on the right, the nuns will usually permit you to enter. At times, the cloister is the venue for modern art shows and, thanks to the Caffè alla Pace, the little piazza has become the core of a trendy café scene.