"[2] Hasan, revered for his austerity and support for "renunciation" (zuhd), preached against worldliness and materialism during the early days of the Umayyad Caliphate, with his passionate sermons casting a "deep impression on his contemporaries.

[3] While fragments of his famed sermons do survive in the works of later authors, the only complete manuscripts that bear his name are apocryphal works such as the Risālat al-qadar ilā ʿAbd al-Malik (Epistle to ʿAbd al-Malik against the Predestinarians),[2] a pseudopigraphical text from the ninth or early-tenth century,[2] and another letter "of an ascetic and hortatory character" addressed to Umar II (d. 720),[2] which is likewise deemed spurious.

[9][3] In his famed Ḳūt al-ḳulūb, the most important work of Basran mysticism, Abu Talib al-Makki says of Hasan: "Ḥasan is our Imām in this doctrine which we represent.

[3] His mother, Khayra, is said to have been a maidservant of one of Muhammad's wives, Umm Salama (d. 683), while his father, Peroz, was a Persian slave who originally hailed from southern Iraq.

[3] According to some scholars, it is "primarily this association with Medina and his acquaintance there with many of the notable Companions and wives of Muḥammad that elevated [Hasan's] importance as an authoritative figure in Muslim religious and historical genealogy.

[3] It was during this latter period that he began to criticize the policies of the governors in Iraq, even stirring up the authorities to such a degree that he actually had to flee for the safety of his life under the reign of Ḥaj̲j̲āj, whose anger Hasan had roused due to his forthright condemnation of Ḥaj̲j̲āj's founding of Wāsiṭ in 705.

"[18] The hagiographic scholar John Renard summarizes the narrative thus: "Hasan once visited the Byzantine Emperor's court, and the vizier invited him to travel with him into the desert.

The vizier explained that each year since the Emperor's handsome young son had died of an illness, these throngs of Byzantine subjects had come to pay respects to the dead prince.

After all these categories of royal subjects had entered and departed, the Emperor and his chief minister would go into the tent and explain to the deceased boy, in turn, how it grieved them that neither their might, nor learning, nor wisdom, nor wealth and beauty, nor authority had been sufficient to prolong his promising life.

"[19] One particular tradition relates that he wept so much praying on his rooftop one day that his abundant tears began to run off "through the downspouts upon a passerby, who inquired whether the water was clean.