He and his sister, María Teresa, were the children of
King Alfonso XIII and
Carmen Ruiz Moragas. Alfonso never acknowledged them publicly, but did ensure that they were cared for after Carmen's death in 1936. Leandro did not learn about his paternity until he was 10 years old. He was not recognized formally by Spain as Alfonso's son until 2004. In 2003, the Spanish Royal House decreed that Leandro could used the surname "Borbón" without having to submit to a DNA test, but refused to recognize his claim to the throne.
