Aḥmad ibn Ḥanbal—according to the report his son ʿAbd Allāh transmitted from him—said: “In my judgment the report of Abū Bishr is weak. Abū Isḥāq narrated from Saʿīd that the age was fifteen.”
This agrees with the report of ʿUbayd Allāh ibn ʿAbd Allāh (1).
Al-Zubayr ibn Bakkār said: “The Messenger of Allāh ﷺ passed away when Ibn ʿAbbās was thirteen years old.”
Abū Saʿīd ibn Yūnus said: “Ibn ʿAbbās campaigned in Ifrīqiyyah with Ibn Abī Sarḥ, and fifteen people from Egypt transmitted from him.”
Abū ʿAbd Allāh ibn Mandah said: “His mother was Umm al-Faḍl, the sister of the Mother of the Believers Maymūnah, and he was born two years before the Hijrah.”
He was light-skinned, tall, with a slight yellowish hue, broad-bodied and handsome, bright-faced, wearing his hair long and dying it with henna. The Prophet ﷺ prayed that he be granted wisdom.
I add: He was the maternal cousin of Khālid ibn al-Walīd al-Makhzūmī.
Saʿīd ibn Sālim reported: Ibn Jurayj told us, saying,
“We were sitting with ʿAṭāʾ in the Sacred Mosque and began recalling Ibn ʿAbbās. ʿAṭāʾ said,
‘I have never seen the moon on the night of the fourth…’”
(1) Ibn Hajar states in Fath al-Bari, 11/76: “The most reliable report is that he was born in the Shiʿb (the mountain pass) three years before the Hijra, making him thirteen at the Prophet’s death. The early biographers agree on this, and Ibn ʿAbd al-Barr declared it sound. With an authentic chain he cites Ibn ʿAbbas: ‘I was born while Banu Hashim were in the Shiʿb.’ This does not conflict with his other statements—‘I had nearly reached puberty,’ and ‘They would not circumcise a boy until he became mature’—because he may have reached maturity and been circumcised after the Farewell Pilgrimage yet before the Prophet’s death. His phrase ‘I was ibn ʿashar (in my tens)’ can be explained by disregarding the partial months, while Ahmad’s version, ‘I was fifteen,’ can be reconciled with ‘thirteen’ by assuming he was thirteen and several months, having been born mid-year. For example, if he was born in Shawwal, he would have three months of the first year that were counted as a full year; the Prophet died in Rabiʿ, giving him three months of the final year. The intervening complete years total thirteen. Those who said ‘thirteen’ ignored the fractional months; those who said ‘fifteen’ rounded them up. Allah knows best.”