Abu Sufiyan ibn Harb

Abu Sufiyan ibn Harb was the leader of the Banu Abd Shams clan of the Quraish tribe, and was the cheiftan of the entire Quraish tribe, making him one of, if not the most powerful men in Mecca during the lifetime of Muhammad. Abu Sufiyan's grand-father was Umayya for whom the Umayyad dynasty is named, and his great-grand father was Abd Shams. Ironically, his great-grandfather's brother was Hashim the great-grandfather of Muhammad. One of Abu Sufiyan's sons was Muawiyah I who established the Umayyad dynasty of caliphs

Abu Sufiyan's position of power made him an enemy of Muhammad, who he viewed as a threat, and who he tried to muzzle and even kill through various methods. The Quraish even began persecuting people who accepted Islam. Even Abu Sufiyans own daughter was not spared from punishment when she accepted Islam. She was thus one of the first Muslims sent to Abyssinia for refuge. The emnity between the Quraish and early Muslims reached such a high pitch that many battles were fought between the two parties. Eventually the two parties would make peace, the Treaty of Hudaybiyya which would eventually be broken. Apparently it was broken when some Muslims were attacked by masked raiders, who the Muslims blamed on the Quraish. This led to the final reconquest of Mecca by the Muslim armies, who took the city peacefully and spared those within. Upon this defeat, Abu Sufiyan voluntarily accepted Islam.