The Basilica of Saint Francis was planned as an Egyptian cross, also known as the T-cross, characterized by a transect that crosses the church at the apse. This particular shape evokes the Tau Saint Francis chose as a symbol of Jesus’ cross and that has now become the identifying mark of the Order. In entering the sacred building therefore one was at the foot of the cross and became part of the mystical body of Christ, which is the Church. The Basilica’s interior is formed by a large single hall, typical of the churches of the mendicant orders: the spaciousness of this structure allowed to host a large number of followers and had a key acoustic function essential to preaching, which in the past took place without the use of technological devices. The absence of side aisles immediately attracts the attention of those who enter towards the altar, the heart of the whole building, where during Holy Mass the Sacrifice of Christ, who died and rose again for our salvation, takes place. The need of the Order to pursue poverty and spirituality is confirmed in the architecture, void of any decoration, yet still able to express the glory of God. In both arms of the transept there are a few chapels, once under the patronage of the most important families in Siena who commissioned the decoration not only to assert their prestige, but also to plead the forgiveness of sins and the . . .