Person

al-Zubayr ibn ʿAbd al-Muṭṭalib

الزبير بن عبد المطلب
Lifespan unknown Banū Hāshim

Full brother of Abdullāh (the Prophet's father) and Abū Ṭālib. A major Quraysh leader. Founder of Ḥilf al-Fuḍūl (the Pact of the Virtuous, c. 590 CE) — a pre-Islamic alliance to defend the wronged in Mecca, which the Prophet ﷺ attended as a young man and later said: "If I were called to it in Islam, I would respond." Died before the Prophet's prophethood.

Significance

Full brother of Abdullāh (the Prophet's father) and Abū Ṭālib. A major Quraysh leader. Founder of Ḥilf al-Fuḍūl (the Pact of the Virtuous, c. 590 CE) — a pre-Islamic alliance to defend the wronged in Mecca, which the Prophet ﷺ attended as a young man and later said: "If I were called to it in Islam, I would respond." Died before the Prophet's prophethood.
Sources: Wikipedia and classical Islamic biographical literature compiled by automated researchers. Every page is being continuously refined — if something looks off, please check back in a few days.