The gates and walls of Oltrarno were built between 1324 and 1327, in the days of the Republic's great struggle with Castruccio Interminelli. Unlike those on the northern bank, they are still in part standing. There are five gates on this side of the river--the Porta San Niccolò, the Porta San Miniato, the Porta San Giorgio, the Porta Romana or Por San Piero Gattolino, and the Porta San Frediano. It was all round this part of the city that the imperial army lay during the siege of 1529 and 1530. On the east of the city, on the banks of the Arno, rises first the Porta San Niccolò--mutilated and isolated, but the only one of the gates that has retained a remnant of its ancient height and dignity. In a lunette on the inner side is a fresco of 1357--Madonna and Child with Saints, Angels and Prophets. Around are carved the lilies of the Commune. On the side facing the hill are the arms of the Parte Guelfa and of the People, with the lily of the Commune between them. Within the gate the Borgo San Niccolò leads to the church of San Niccolò, which contains a picture by Neri di Bicci and one of the Pollaiuoli, and four saints ascribed to Gentile da Fabriano. It is one of the oldest Florentine churches, though not interesting in its present state. There is an altogether untrustworthy tradition that Michelangelo was sheltered in the tower of this church after the capitulation of the city, but he seems to have been more probably in the house of a trusted friend. Pope Clement ordered that he should be sought for, but left at liberty and treated with all courtesy if he agreed to go on working at the Medicean monuments in San Lorenzo; and, hearing this, the sculptor came out from his hiding place. It may be observed that San Niccolò was a most improbable place for him to have sought refuge in, as Malatesta Baglioni had his headquarters close by. Beyond the Porta San Niccolò is the Piano di Ripoli, where the Prince of Orange had his headquarters. Before his exile Dante possessed some land here. It was here that the first Dominican house was established in Tuscany under St Dominic's companion, Blessed John of Salerno. Up beyond the terminus of the tramway a splendid view of Florence can be obtained.