Alvar was the son of unknown parents. The date and place of his birth have not been found.
His wife was Leonor Enríquez de Quiñones. They were married, but the date and place have not been found. They had no known children.
| Attribute | Date | Description | Details | Source | Multimedia | Notes |
|---|---|---|---|---|---|---|
| Nobility Title | conde de Trastámara y de Villalobos | |||||
| Nobility Title | marqués de Astorga 1° |