Leontes van de Montague is the father of Tybalt and Romeo, is the former husband of Lady Portia , before the true nature of Ophelia was revealed.
He was actually not from the house of Montague. His mother was a e and his father was a Capulet. Because His 'father' abandoned his mother, he started to hate the Capulets. To gain revenge, He was adopted into the House of Montague. Leontes poisoned the Heir of the Montague house which resulted in him becoming the heir. At a ball, Leontes met Tybalt's Mother; a Capulet daughter. Two things known are that either he abandoned her, and also, since the will of Escales needs a Capulet girl as a sort of sacrifice, she probably died from that. Therefore if Montague truly loved Tybalt's mother, he would have become even more angered with the Capulet family.