In his political life, Galeazzo II Visconti worked to expand the power of his family. The Visconti first became the hereditary rulers of Milan on May 31, 1349 when the General Council of Milan created a statute that the office of dominus generalis would be inherited by the legitimate male descendants of Matteo Visconti, who was the grandfather of Galeazzo II Visconti. One of Matteo Visconti's sons, Luchino Visconti, wanted his son Luchino Novello to succeed him as signore of Milan, but this proposal was rejected by Galeazzo II, Matteo II and Bernabò Visconti, who were the sons of Stefano Visconti. After the death of Giovanni Visconti, who was the brother of Galeazzo, Luchino and Stefano Visconti, the General Council of Milan created another statute which proclaimed that Galeazzo II, Matteo II and Bernabò Visconti were to govern Milan as co-rulers because they were the only male adult descendants of their grandfather Matteo Visconti. Other territories under Visconti jurisdiction were to be divided among them as well. Matteo II Visconti died five months after he and his two brothers obtained the title of imperial vicar from the Holy Roman Emperor and although the exact cause of his death was unknown, he left his brothers Galeazzo II and Bernabò as the two remaining co-rulers of Milan.