Her marriage to King Denis of Portugal was arranged in 1281 when she was 10 years old, receiving the towns of Óbidos, Abrantes and Porto de Mós as part of her dowry. It was only in 1288 that the wedding was celebrated, when Denis was 26 years old, while Elizabeth was 17. Denis, a poet and statesman, was known as the Rei Lavrador, because he planted a large pine forest near Leiria to prevent the soil degradation that threatened the region. Elizabeth quietly pursued the regular religious practices of her youth and was devoted to the poor and sick. Such a life was taken as a reproach to many around her and caused ill will in some quarters. Eventually, her prayer and patience succeeded in converting her husband, who had been leading what she considered a sinful life. Elizabeth took an active interest in Portuguese politics and was a decisive conciliator during the negotiations concerning the Treaty of Alcañices, signed by Denis and Fernando IV of Castile in 1297. In 1304, the Queen and Denis returned to Spain to arbitrate between Fernando IV of Castile and James II of Aragon, brother of Elizabeth. She had two children:
Elizabeth would serve as intermediary between her husband and Afonso, during the Civil War between 1322 and 1324. The Infante greatly resented the king, whom he accused of favoring the king's illegitimate son, Afonso Sanches. Repulsed to Alenquer, which supported the Infante, Denis was prevented from killing his son through the intervention of the Queen. As legend holds, in 1323, Elizabeth, mounted on a mule, positioned herself between both opposing armies on the field of Alvalade in order to prevent the combat. Peace returned in 1324, once the illegitimate son was sent into exile, and the Infante swore loyalty to the king.
Dowager Queen
After Denis' death in 1325, Elizabeth retired to the monastery of the Poor Clare nuns, now known as the Monastery of Santa Clara-a-Velha in Coimbra. She joined the Third Order of St. Francis, devoting the rest of her life to the poor and sick in obscurity. During the great famine in 1293, she donated flour from her cellars to the starving in Coimbra. She was also known for being modest in her dress and humble in conversation, for providing lodging for pilgrims, distributing small gifts, paying the dowries of poor girls, and educating the children of poor nobles. She was a benefactor of various hospitals and of religious projects. Her body was transferred to the main chapel, where it was buried in a sarcophagus of silver and crystal.
She was the subject of a 1947 Portuguese-Spanish film, The Holy Queen, in which she was played by Maruchi Fresno. In Portuguesepopular culture, she is commonly associated with a "miracle of the roses".