House of Lara
Osorio died at the hands of his son-in-law, Fernando Rodríguez de Castro, husband of his daughter Constanza, at the Battle of Lobregal in March 1160, fighting on the side of the House of Lara in the civil war for control of the regency of the young Alfonso VIII. Osorio's widow continued to rule Villalobos, at least until 3 November 1167. She also made property grants to the Hospitallers in 1161 and 1163.