The Via delle Cerchia, skirting the older circuit of walls, brings us to the piazza and church of Sant' Agostino, an ancient edifice completely modernised in the eighteenth century. Over the second altar on the right is the Crucifixion, a late work by Perugino, with a number of saints and the Madonna at the foot of the Cross; the group of St Augustine kneeling, with St Monica standing behind him, is finely conceived. The chapel of the Blessed Sacrament is the chapel of the Piccolomini; the decorations of the altar were undertaken by the Archbishop Ascanio Piccolomini in 1596, "for the worship of God Almighty and the honour of his own family." The altarpiece, Bazzi's Adoration of the Magi, in spite of the blackening of the shadows and the overcrowding of the figures, is an exceedingly fine work, thoroughly Lombard in composition and feeling, the beautiful young King on the right curiously recalling Luini's types; "there is," says Vasari, "a head of a shepherd between two trees, which seems verily alive," and which is said to be the painter's own portrait. The picture was painted for two of the Arduini family, and the name and arms of the Archbishop Ascanio are obviously a later addition. On the left is a marble statue of Pius II. by Duprè, and on the right the Massacre of the Innocents by Matteo di Giovanni. This latter picture shows sufficient dramatic energy and sense of beauty to make us wish that these were displayed upon a less horrible subject. The groups of unconcerned children and the classical bas-reliefs remind us of Matteo's admirable work upon the pavement of the Duomo, but the king and soldiers are mere hideous caricatures. In the choir is a picture in three divisions--a work in which Mr Berenson calls attention to the "extraordinary grace of motion and beauty of line"--by Simone Martini, representing the blessed Agostino Novello (a courtier of King Manfred, who became a hermit) and four scenes of his miracles. The later Sienese school is fairly well represented by a Way to Calvary by Ventura Salimbeni, and a curious picture (on the last altar to the left of the choir) by Rutilio Manetti, representing the Temptation of St Antony. Beyond Sant' Agostino is the Porta Tufi, so often mentioned in the story of Siena, outside which, on the site of the present Cimitero della Misericordia, was the famous convent of the Olivetani where Bernardo Tolomei died. From the piazza, the Via Sant' Agata leads down to the church of San Giuseppe, where, under a picturesque arch, we re-enter the older circle of walls by the Via Giovanni Duprè, in which the house is shown where Siena's great modern sculptor was born.