During the 15th century a new refectory was built in 1484, with a dormitory above it.
Another enlargement of the monastery progressed throughout the 16th century, bringing the complex to its present dimensions and general appearance.
Beginning in 1510, this included a second dormitory and a second interior cloister (clausura, patio), which was done largely at the expense of the Bishop of Pienza, Girolamo Piccolomini.
The bishop had two of his brothers in the Lecceto community, i.e., Lattanzio (Prior in 1533-1534) and Rafaello. The upper part of that cloister was not added until 1548-1550.
A life-size fresco of the legend of Saint Augustine talking about the Trinity to a child on the sea shore was painted on a wall of this cloister in 1712 by Bartolomeo Fellicuti, but is now almost effaced.
In warfare during 1554 in which soldiers of Florence besieged Siena near Lecceto, troops invaded the hermitage (eremo), plundered it, and expelled all but two of the Augustinians.
Once the warfare ended, restoration of the monastery began. In its subsequent repairs and decoration, the church was given a decidedly baroque style.
This style of chapel was the initiative of Camillo Nocci O.S.A. as Prior of Lecceto in 1611-1615, and has been judged by some experts to have been an aesthetic disaster, and even an artistic desecration. He obliterated earlier paintings, and added an ill-advised balcony above the main door.
In the seventeenth century, Ambrogio Landucci O.S.A., who was elected Augustinian Prior there in 1634, enriched Lecceto with a library and the archives.
He also wrote two books: the Sacred Ilicetana Sylva and the Sacred Leccetana Forest.
(Continued on the next page.)