Alessandro was the son of Duke Ottavio Farnese of Parma and Margaret, the illegitimate daughter of the Habsburg Emperor Charles V. Thus Alessandro was the nephew of Philip II of Spain and of Don John of Austria.
Alessandro was the son of Duke Ottavio Farnese of Parma and Margaret, the illegitimate daughter of the Habsburg Emperor Charles V. He had a twin brother, Charles, who only lived one month. His mother was the sister of Philip II of Spain and of Don John of Austria.