Former chapel dedicated to Saint Ursula and the Eleven Thousand Virgins, commissioned by Cardinal Mota to the architect Carlos Mardel in 1740. The work was executed by the master stonemasons Manuel Martins and Aleixo Rodrigues, in which stands out the rich polychrome marbles and also the sculptures attributed to the Paduan sculptor João António Bellini.

Behind the chapel of Saint Anthony there is another chapel dedicated to the same saint, inside the church. This area is believed to be the location where Saint Anthony’s monastic cell was, during his time living here, early 13th century. Given the importance of this place, the mother of Fernando de Bulhões (Saint Anthony’s baptismal name) was buried here. The Saint initiated his clerical life in this Monastery, as canon regular of Saint Augustine. The passage through this religious order was essential for his education, leading him to be later recognized as a Doctor of the Church.