Yahya bin Bukayr said: Al-Zubayr bin al-Awwam (may Allah be pleased with him) was martyred on the day of the Battle of the Camel, in Jumada (I do not know whether the first or the second), in the year 36 AH.
Yahya said: Al-Layth told me, through Abu al-Aswad, that Urwah informed him that al-Zubayr (may Allah be pleased with him) accepted Islam at the age of eight, and his kunyah was Abu Abdullah. If the Messenger of Allah (peace and blessings be upon him) stayed in Makkah for thirteen years, then on the day he was martyred he was fifty-seven (57) years old; and if he (peace and blessings be upon him) stayed for ten years, then al-Zubayr was fifty-four (54) years old.
Hadith Referenceالمعجم الكبير للطبراني / العشرة / 237