Trade and early belief
Talha belonged to the Taym clan of Quraysh and accepted Islam early. He faced persecution in Makkah before settling in Madinah, where he remained active in trade and community life.
Source: TDV Encyclopaedia of Islam — Talha ibn Ubayd Allah
The first civil war
Umar nominated Talha to the succession council, although TDV reports that he was absent during the selection. Talha later opposed Ali in the conflict leading to the Battle of the Camel. He died in 656; accounts differ about the immediate circumstances.
Source: TDV Encyclopaedia of Islam — Talha ibn Ubayd Allah
