Maximilian II, Holy Roman Emperor
In his turn, Philip III was the son of Philip II of Spain and Anna of Austria who was, herself, a daughter of Maximilian II, Holy Roman Emperor and Maria of Spain. Philip II and Maria of Spain were siblings, being both children of Charles V, Holy Roman Emperor and Isabella of Portugal. María Teresa, therefore, like many Habsburgs, was a product of years and generations of royal intermarriage between cousins.