He is Hassan ibn Hassan ibn Hassan ibn ‘Ali ibn Abi Talib radiya Llahu ‘anhum.
Agnomen: His agnomen was al Muthallath, due to him being the third person named Hassan, after his father and grandfather.
Hadith: He narrates from his father and mother. Those who narrate from him are Fudayl ibn Marzuq, ‘Umar ibn Shabib, Muhammad ibn Abi Sarah.
He was martyred alongside his brothers in prison. His age at the time of his demise was 68.
His statement to a person who was exaggerating regarding them, the Ahlul Bayt, is a prime example of his eloquence and strong faith:
Love us for the sake of Allah if we obey Allah. If we disobey Allah then hate us! Had Allah made familial links to the Messenger salla Llahu ‘alayhi wa sallam a means of benefit without obedience then the most eligible for that would have been his father and mother.
Previously, we mentioned the manner in which Sayyidah Fatimah bint Hussain rahimaha Llah, his mother, described him before Hisham ibn ‘Abdul Malik, when she said, “As for Hassan, he is our voice.”
The scholars had high regard for him, and despite hardly any narrations being narrated by him, they have stilled declared him to be reliable.
The upbringing of their mother and the life lessons imparted by her left a deep mark on her sons and strengthened the bonds of love between them; each one of them possessing deep love for his brother ready to give preference to them over themselves. Hassan al Muthallath is an excellent example of this. Al Asfahani reports:
When ‘Abdullah ibn Hassan was imprisoned, his brother—Hassan ibn Hassan—took a solemn vow that he would not apply oil, Kuhl (surma/antimony), wear fine clothes, and eat anything appetising as long as ‘Abdullah is imprisoned.
This was the character of this devout ascetic worshipper; who was raised and nurtured by Fatimah bint Hussain rahimaha Llah.
 Tahdhib al Tahdhib, 2/230, # 486.
 Ibid, 7/72, # 169; Sunan Ibn Majah, # 3296. Al Albani said it is Hassan Li Ghayrihi. It is reported in other books of Hadith such as Sunan al Tirmidhi, Sunan al Darami, and al Mujam al Kabir with variant wording.
 Mashahir ‘Ulama’ al Amsar, 1/62.
 Maqatal al Talibiyin, pg. 171.