Cabeza de Vaca's father and grandfather died around 1506 and his mother died in 1509, leaving behind a modest estate for her seven children. His younger siblings went to live with their aunt but Álvar had already entered the service of Juan Alfonso Pérez de Guzmán, 3rd Duke of Medina Sidonia in 1503. The house of Medina Sidonia was one of the most powerful in Castile and was a dominant force in Seville, the commercial center of Spain's growing overseas empire. Cabeza de Vaca served as a page and then chamberlain for the duke. In 1511 he traveled to Italy to fight against the French. In February 1512 he took part in the Battle of Ravenna where the Spanish were badly defeated and Cabeza de Vaca was wounded. He later served as the royal standard-bearer in Gaeta, near Naples.