Complex sentence: Sancia, Queen of Castile, whose husband has been killed in battle, also believe that their son, Garcia has been killed, plans to marry the Saracen prince, Ircano, against the advise of her minister, Rodrigo.
Split into simpler sentences: Sancia, Queen of Castile, whose husband has been killed in battle, also believes that her son, Garcia has been killed. She plans to marry the Saracen prince, Ircano, against the advice of her minister, Rodrigo.