The Monastery of Saint Denis (Portuguese: Mosteiro de São Dinis) is located in the city of Odivelas, near Lisbon, in Portugal. The feminine Cistercian convent was founded by King Dinis I and was built during the 14th century in Gothic style. It is the burial place of the king. Since 1900, it houses the Instituto de Odivelas, a military school for young girls.
According to a legend, King Dinis was hunting near Beja when he was attacked by a bear, which made him fall off his horse. Fearing for his life, Dinis swore to found a monastery if he could escape alive. In the combat that ensued, the King managed to plunge his dagger into the heart of the beast and kill it. That would be the origin of the monastery of Odivelas.
What is known for certain is that King Dinis founded the feminine Cistercian monastery in 1295 on an isolated spot of the Portuguese hinterland, around which the village of Odivelas developed. The works proceeded swiftly, being mostly finished some ten years after the foundation stone had been laid. King Dinis I died in 1325 and was buried in a Gothic tomb the church of the monastery. One of the king's daughters, Princess Maria Afonso (d. 1320), is also buried here.
The existence of a royal palace in Odivelas meant that the monastery was favoured by some Portuguese monarchs during the Middle Ages. An important figure associated with the monastery is Queen Philippa of Lancaster, who lived some time in the monastery until her death in 1415. The Queen was provisionally buried in the church of the monastery until being translated to the Monastery of Batalha.
In the early 16th century there were several improvements in the monastery, including the building of a new cloister in Manueline style and a Renaissance gallery by the entrance. In the early 18th century, the monastery was frequently visited by King John V, who had a scandalous affair with Mother Paula (1701-1768), abbess of the monastery. They had an illegitimate son, José, one of the so-called Children of Palhavã.