After having spent several years in Assisi, Pisa and Orvieto, only occasionally returning to Siena for very brief periods during which he worked in the Palazzo Pubblico (on one occasion to retouch the Maestà, on another to paint some works that are no longer extant), Simone Martini actually returned to Siena on a stable basis. This appears to have been a rather calm period of his life and it was at this time that he married Giovanna Memmi: perhaps feeling tired after his travels, working for so many different patrons in different places, Simone decided to settle in his home town.  It was sometime around 1325 and Simone was a well established painter, at the height of his artistic maturity. His experiences working for the House of Anjou and the Franciscans, in international environments where political interests frequently took the place of religious spirit and where art became an effective means of visualizing and promoting temporal power, had made Simone much more a man of the world: he had set off from Siena as a talented but simple Sienese painter, and he returned as a famous artist, selfconfident and experienced. Back in Siena, Simone worked for the Government of the Nine adding more and more splendid works to the Palazzo Pubblico, year after year; most of these paintings have not survived and we only know about them from the payments recorded in the Biccherna ledgers. It was during this second Sienese period that Simone painted some of his most famous paintings, such as the Blessed Agostino Novello Altarpiece, the celebrated fresco of Guidoriccio da Fogliano and the Annunciation now in the Uffizi, the only one that is actually signed and dated.
The story of the Blessed Agostino Novello is an example of that form of popular religious spirit that grew up in the towns of Tuscany in the late 13th century and the early 14th. The Church's official saints were considered too remote by the people and spiritually so different from the reality of the times that they could not entirely satisfy the religious fervour that developed in those years. The people felt that they needed more tangible examples of holiness, more closely connected to daily reality, rather like St Francis of Assisi had been. As a result, some of the better known citizens, whose charitable and religious deeds were known to all (and in may cases miracles were attributed to them), were canonized as saints or blessed.
Agostino Novello was one of these figures. After a brilliant career both as a layman and as a cleric (he studied law at the University of Bologna and became personal councillor to King Manfred, the son of Ludwig II; when he joined the Augustinian Order he became Prior General), Agostino Novello then renounced community life and retired to the hermitage of San Leonardo al Lago, near Siena.
After his death in 1309, the worship of this saintly man spread so fast that the monks of his Order tried to have him nominated patron saint of the city: through the veneration of a member of their Order, the Augustinians were sure to gain prestige and power. But Agostino was not made patron saint of Siena, despite the fact that he must indeed have been the object of great veneration to judge by the impressive funerary monument that was built for him.
Now in the Pinacoteca in Siena, the painting hung originally in the church of Sant'Agostino, probably above the wooden sarcophagus in which the Blessed Agostino was buried; together with the altar consecrated to him, these two elements formed a burial monument. The dating of this altarpiece can only be approximated. We can only suppose that it was already finished and in place on the occasion of the celebrations in honour of the Blessed Agostino held in 1324 and for which the Commune of Siena allotted a huge sum of money.
The iconography, at least for modern observers like us, is clear but not that simple to understand. The central area, framed by a multifoiled ogival arch, encloses the figure of Agostino, who is given a saint's halo even though he had not been canonized. The wooded landscape, the old hermits in the medallions and the scene of the conversation with the angel (an episode that does not appear in any of the biographies) are all references to the hermit's life he led at San Leonardo al Lago. On the other hand, the face of Agostino, portrayed still as a young man, the red book he carries (perhaps the Constitutiones of the Order, which he had drawn up himself), as well as the fact that the miracles are all taking place in a very realistically described Siena, all suggest Agostino's political commitments and the pastoral duties he performed in the city.
The miraculous powers of the Blessed Agostino are fully displayed in the scenes depicted at the sides of the central area; they are framed by trefoiled round arches and illustrate four miracles. The idea of Agostino's holiness, stressed by the sudden appearances of winged angels, was intended to capture the mediaeval public's religious sensitivity: the victims of the terrible accidents are for the most part children.