Siena Cathedral
Giovanni was the son of sculptor and architect Agostino da Siena (c. 1285 – c. 1347; also known as Agostino di Giovanni) and the sculptor brother of Domenico di Agostino. Like the rest of his family, most of his work was sculptural commissions of the newly built Gothic Siena Cathedral. He sculpted a monument to Bishop Guido Tarlati in 1330. He also rendered a relief entitled "Madonna and Child with Saints Catherine and John the Baptist" between 1340 and 1348.