What was the original name of Abu Taalib? Did he help the Prophet, sallallaahu ‘alayhi wa sallam, at any time and did he refuse to let him, sallallaahu ‘alayhi wa sallam, marry a daughter of his named Fatimah, the sister of Ali, may Allaah be pleased with him?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The real name of Abu Taalib is ‘Abd Manaaf.  He helped the Prophet, sallallaahu ‘alayhi wa sallam, during his life and protected him from Quraysh. However, he died as a Kaafir (unbeliever) and did not embrace Islam according to the consensus of the scholars of Islam.

As regards his refusal to marry his daughter Faatimah to the Prophet, sallallaahu ‘alayhi wa sallam, we do not know have any proof of that.

Allaah Knows best.