摘要:This article explores the relationship between the dreams and the death of one of the Portuguese princesses from the dynasty of Avis, D. Joana, daughter of the king D. Afonso V and the queen D. Isabel, who lived in two worlds: first as a princess in the royal court, after as Dominican religious in the Convent of Jesus de Aveiro and there she was buried. It investigates the medieval dreams world and the mystic universe of a princess who lived in the 15th century and was canonized only in the 20th century. It also shows the causes of her death by the contemporaneous medicine. Key words: D. Joana, dreams, death.