Maria was married by her brother in his ambition to place his father's issue on the thrones of Castile and Aragon. The marriage took place in simplicity. Maria was occasionally politically active on behalf of her brothers, the princes of Aragon; she disregarded her husband's policy in favor of her brothers and the relationship between Maria and John was somewhat tense.
After her death on 18 February 1445, her husband married Isabella of Portugal and they became the parents of Isabella I of Castile. Maria has no descendants today, her line having gone extinct within a few decades of her death.
^de Sousa, Antonio Caetano (1735). Historia genealogica da casa real portugueza [Genealogical History of the Royal House of Portugal] (in Portuguese). Vol. 2. Lisboa Occidental. p. 497.