Denis, Lord of Cifuentes

Denis of Portugal was an infante of Portugal. He was the son of Portuguese King Peter I and a Galician noblewoman named Ins de Castro who had arrived in Portugal as a maid of princess Constance of Castile, recently married to Pedro I .

He married in 1372 Joan of Castile, 2nd Lady of Cifuentes, born c. 1360, illegitimate daughter of Henry II of Castile by Juana, 1st Lady of Cifuentes, born c. 1340, from whom he had two sons and a daughter

Source: Wikipedia