20 October - Irene is born into a wealthy family in Nabância, now Tomar. She is sent by her parents to the local monastery where she is placed under the guardianship of a tutor, the monk Remigius.

One day, Britald, a young nobleman, sees her coming out of mass and falls in love with her. Irene rejects him because she wants to consecrate herself to God and Britald falls into a deep depression. Remigius, jealous of Britald's passion, prepares a herbal tea that puts Irene into a trance and leads to a nervous pregnancy. For this she is expelled from the monastery and Britald, jealous and aware of the incident, hires a soldier who disguises himself as an old vagrant and kills her with his sword.

The body is thrown into the river Nabão and is carried by the torrential river Zêzere to the sandy banks of the Tagus, to Scalabis, a town which, out of devotion and in her memory, changes its name to Santarém (Saint Irene). A church was built on the sandy mound where her body was found. The saint's body is miraculously preserved in a state of incorruptibility for several centuries.