In the beginning of 1383, the political situation in Portugal was not peaceful. Beatrice was the king's only child, after her younger brothers death in 1380 and 1382, and heir to the throne. Her marriage was the political issue of the day and inside the palace, factions lobbied constantly. Ferdinand arranged and cancelled his daughter's wedding several times, before settling for his wife's first choice, king Juan I of Castile. Juan had lost his wife (princess Leonor of Aragon) in the year before and was happy to take the Portuguese heiress. The wedding took place in May 17 1383 in the Portuguese city of Elvas. Beatrice was only eleven years, old enough, however, for a marriage in the 14th century.
King Ferdinand of Portugal dies shortly afterwards, in October 22 1383. According to the treatise between Castile and Portugal, the Queen Mother, Leonor Telles de Menezes, become regent in the name of her daughter and son-in-law. But not everybody in Portugal was happy about this state of affairs. The loss of independence was unthinkable for the majority of Portuguese nobles. A rebellion led by the Master of the Order of Aviz, future Joćo I of Portugal started in that year, leading to the 1383-1385 Crisis.
Juan I of Castile invades Portugal in 1384 to fight for his newly born son's (Miguel 1384-1385) rights to the crown. This war would end in the next year, with the utter defeat of Castile in the Battle of Aljubarrota. In the aftermath of this battle, Joćo I of Aviz would became uncontested king of Portugal. Beatrice was no longer heir to the throne, just the Consort Queen. She died in 1410 in Madrigal (Castile).