Banu Abd Shams refers to a clan within the Meccan Quraishi tribe. The clan takes its name from 'Abd Shams bin Abd Manaf. Abd Shams was a brother of Hashim whose descendants would be known as the Banu Hashim clan of which Muhammad was a member.
The Banu Abd Shams tribe was led by Abu Sufiyan ibn Harb, and was bitterly opposed to Muhammad for most of his prophethood. Only after Muhammad reconquered Mecca did they stop opposing him. This clan also spawned the Umayyad dynasty, which takes its name from the son of 'Abd Shams, Umayya. Uthman ibn Affan was also a member of this clan, but he did not follow suit and converted to Islam not long after Muhammad started preaching the message.
