Fresco cycle of St Augustine in the Sant'Agostino, San Gimignano (1464-65)

By 1463 at the latest, Benozzo had left his native city and moved to San Gimignano for four years, until 1467. He had left Florence because of the plague, for towns at higher altitudes such as San Gimignano were thought to be less at risk. Here, in collaboration with several assistants, he produced his main work, the decorations of the apsidal chapel of the church of Sant'Agostino (1464-65). The single-aisled hall church with three apsidal chapels and an open roof truss, built by the Augustinian canons between 1280 and 1298, is a typical example of the Gothic architecture of the mendicant orders in central Italy.

Benozzo was given the commission by Fra Domenico Strambi, a learned Augustinian monk belonging to the monastery who in 1449 had been given a grant by the town to study theology at the Sorbonne in Paris. The paintings were produced within the contemporary context of the reformation of the monastery of Sant'Agostino. The intention was to merge it with the Augustinian order of San Salvatore in Lecceto near Siena. The choir, being the place where the community of monks assembled, was decorated with a didactic program of the life and work of St Augustine. The cycle of St Augustine is one of the main works of Tuscan narrative art dating from the middle of the century. It can take its place alongside the fresco cycle of the Legend of the True Cross (1453/54) by Piero della Francesca in Arezzo and Donatello's Passion Pulpit and Resurrection Pulpit (1460-62) in San Lorenzo in Florence.

The cycle depicts 17 scenes from the life of the Father of the Church. When selecting the scenes from the legend of St Augustine, Benozzo had to create his own iconography without using models, and Domenico Strambi helped him to achieve this. The distinguishing feature of the pictorial program is a simple construction of scenes which shows the protagonists in realistic rural, urban or architectural surroundings. The 17 pictures, which are arranged in three rows, use the traditional horizontal direction of reading, from the bottom left to the top right. Strambi is thought to be the author of the Latin inscriptions which comment on the events in each case. An innovation was the uniform system of architectural frames, in which painted pilasters separate each of the pictures from each other. It represents a direct preliminary stage to Domenico Ghirlandaio's painted wall structure of several loggia-like storeys.

Benozzo arranged the life of St Augustine in three sections. In the lowest register he depicts the education, teachings and journeys of the saint.

The middle register shows his path to Christian faith:

Finally, in the lunette fields the culmination of his journey through life appears.

Here, as in Montefalco, the cycle is read from the bottom upwards, and as a result should be interpreted as a painted metaphor of a striving to reach God.

The vaulting shows the four Evangelists on concentrically painted clouds, creating the impression of a circular vault.

As in the cycle of St Francis in Montefalco, the cycle of St Augustine does not depict any miracles or posthumous events, but portrays the saint as a student, teacher and scholar. This corresponded to the new humanist opinion of the Father of the Church, who combined classical learning, a high regard for Plato and the art of rhetoric with the religious zeal of Christianity. St Augustine was born in 354 in Tagaste (Numidia, now Algeria), the son of Patricius, a pagan, and the Christian Monica. The father did not have any decisive influence on him, though that of the mother was to prove to be a lasting one.