Ferdinand I of Portugal
Upon Henry II's death in 1379, his son John came to power as John I of Castile. During his reign, John took Beatrice, daughter of King Ferdinand I of Portugal, as his second wife. On the basis of this marriage, John made an unsuccessful claim to the throne of Portugal upon Ferdinand I's death in 1383, a move that possibly could have led to the unification of all of the Iberian Peninsula. John died very unexpectedly in 1390.