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 is His slave and Messenger.
‘Ali ibn Abi Taalib married Faatimah in the second year of Hijrah, and he consummated the marriage with her after the battle of Badr. The children he had from her are as follows: Al-Hasan, Al-Husayn, Muhsin, Zaynab and Umm Kulthoom, as mentioned in Al-Bidaayah wan-Nihaayah by Ibn Katheer .
Ibn Hajar said in Al-Isaabah fi Tamyeez As-Sahaabah:
“Ali ibn Abi Taalib ibn ‘Abdul-Muttalib ibn ‘Abd Manaf Al-Haashimi Al-Qurashi Abul-Hasan was the first person to embrace Islam, according to the view of many scholars. According to the correct opinion, he was born ten years before the commission of Muhammad as a Prophet . So his age when he married Faatimah was twenty-five years old approximately.
Then, after the death of Faatimah he married other wives, among whom were:
1. Umm Al-Baneen bint Haraam Al-Kalbiyyah. He had the following children with her: Al-‘Abbaas, Ja'far, ‘Abdullaah and ‘Uthmaan. They were all killed with Al-Husayn, may Allaah be pleased with all of them.
2. Layla bint Mas’ood bint Khaalid An-Nahshaliyyah At-Tameemiyyah. He had the following children with her: ‘Ubaydullayh and Abu Bakr.
3. Asmaa’ bint ‘Umays Al-Khath’amiyyah. He had the following children with her: Muhammad Al-Asghar and Yahya.
4. Umaamah bint Abi Al-Aas, who was the daughter of Zaynab, the daughter of the Prophet . He had the following child with her: Muhammad Al-Awsat.
5. Umm Sa’eed daughter of ‘Urwa ibn Mas'ood Ath-Thaqafiyyah. He had the following child with her: Umm Al-Hassan.
6. Mukhbi’ah bint Emri’ Al-Qays ibn 'Adiyy Al-Kalbiyyah.
He also married female slaves, who were: As-Sahbaa bint Rabee’ah At-Taghlabiyyah, who was among the captives who were raided by Khalid ibn Al-Waleed in Ayn Tamr, and he married the female slave Khawlah bint Ja’far Al-Hanafiyyah, who gave birth to Muhammed, who was known as Ibn Al-Hanafiyyah.
As regards the number of the children of Al-Hasan they were twelve sons, as mentioned by Ath-Thahabi in Siyar A’laam An-Nubalaa’: the children of Al-Hasan were: Al-Hassan, Zayd, Talhah, Al-Qaasim, Abu Bakr, Abdullaah – who were killed in Karbala with their martyr uncle – and ‘Amr, ‘Abdur-Rahmaan, Al-Husayn, Muhammad, Ya’qoob, and Ismaa’eel. So, these are the male children from al-Hasan .
As regards the number of children of Al-Husayn they are four, as Ath-Thahabi said in As-Siyar: the children of Al-Husayn were: ‘Ali Al-Akbar, who was killed with his father, and ‘Ali Zayn Al-’Aabideen, who had many children, and Ja’far and ‘Abdullaah, who (both) did not have any children.”
Allaah knows best.