- (1355-1398?) First son of Enrique II of Castile and Elvira Íñiguez, out of wedlock.
- Married Isabel, illegitimate daughter of King Fernando of Portugal as part of the conditions established by the peace treaty of Santarém. Though the treaty was signed in 1373, the actual marriage only took place in 1375, when the bride was eleven years of age. [Fernando, ch. 84]
- Alfonso Enríquez married against his will and only out of fear for his father. As soon as King Enrique II died, he asked for an annulment. [Fernando, ch. 95]