Afonso III of Portugal
Luís was born in Portugal, son of Gomes de Alpoim, a knight of Afonso III of Portugal and Ximena Pereira, daughter of Gonçalo Pereira, Lord of Castro Verde. His wife was Dominga Cabral, daughter of João de Sella Cabral, Lord of Pinhel. Alpoim was descendant of Martim de Freitas, Alcaide of Coimbra.