His nearest kin were members of the three connected Valencian families of Borgia, Mila (or Mella), and Lanzol.

One of the sisters of Calixtus, Catarina Borgia, was married to Juan Mila, Baron of Mazalanes, and was the mother of the youthful Juan Luis.

Isabella, the wife of Jofre Lanzol, a wealthy nobleman of Xativa, was the mother of Pedro Luis and Rodrigo, and of several daughters.

The uncle adopted these two nephews and gave them his family name,--thus the Lanzols became Borgias.
In 1456 Calixtus III bestowed the purple upon two members of the Mila family: the Bishop Juan of Zamora, who died in 1467, in Rome, where his tomb may still be seen in S.Maria di Monserrato, and on the youthful Juan Luis.

Rodrigo Borgia also received the purple in the same year.
Among other members of the house of Mila settled in Rome was Don Pedro, whose daughter, Adriana Mila, we shall later find in most intimate relations with the family of her uncle Rodrigo.
Of the sisters of this same Rodrigo, Beatrice was married to Don Ximenez Perez de Arenos, Tecla to Don Vidal de Villanova, and Juana to Don Pedro Guillen Lanzol.[1] All these remained in Spain.