The family of Sayyidah Fatimah rahimaha Llah is a collection of pearls from the Ahlul Bayt, Sayyidah Fatimah rahimaha Llah having left a distinct mark on the character of each of them. Such was her impact on her family; an ideal of goodness with not a blemish on any of them.
The most significant of those that make up her family is her pious husband, the beloved, who accompanied her father, Sayyidina Hussain radiya Llahu ‘anhu, in Karbala’ where he sustained a number of injuries. He is Hassan al Muthanna ibn Hassan ibn ‘Ali ibn Abi Talib radiya Llahu ‘anhum, son of the beloved grandson of the Prophet salla Llahu ‘alayhi wa sallam. 
Agnomen: His agnomen was Abu Muhammad.
Residence: He resided in Madinah.
Brothers: His brothers were Zaid, Talhah, Abu Bakr, and ‘Abdullah. Abu Bakr and ‘Abdullah were martyred alongside their uncle, Sayyidina Hussain radiya Llahu ‘anhu, in Karbala’.
Father and grandfather: He has the noblest of fathers and grandfathers. His father was Sayyidina Hassan radiya Llahu ‘anhu—the leader of the youth of Paradise—and his grandfather was Sayyidina ‘Ali ibn Abi Talib—the fourth Rightly Guided Khalifah and one of the Ten Promised Paradise.
Paternal grandmother: His paternal grandmother was Fatimah al Zahra’ bint Muhammad salla Llahu ‘alayhi wa sallam—the leader of the Prophets and all of Mankind—and her mother was Sayyidah Khadijah bint Khuwaylid radiya Llahu ‘anha—one of the four leaders of the women of Paradise, her daughter the second of the four.
Paternal granduncles: His paternal granduncle is Jafar ibn Abi Talib, the martyr, who was granted wings in Paradise.
Great granduncle: His great granduncle was Hamzah ibn ‘Abdul Muttalib—the Lion of Allah and His Messenger salla Llahu ‘alayhi wa sallam—the leader of the martyrs.
One can gauge from the above the type of household he was raised in—one filled with goodness, morality, and faith; with such role models that left an indelible impression on his character and personality.
Wives: Hassan al Muthanna married Fatimah bint Hussain, Umm Musa bint ‘Umar al Atraf ibn ‘Ali ibn Abi Talib, Umm Fadl bint Muhammad ibn al Hanafiyyah, and Ramlah bint Sa’id ibn Zaid.
Thus, he was son-in-law to three of his uncles, having married three of his cousins, an indication of the love and admiration his uncles had for him.
Hadith: He narrates Hadith from his father— Hassan ibn ‘Ali, ‘Abdullah ibn Jafar, and his wife, Fatimah bint Hussain radiya Llahu ‘anhum.
Al Nasa’i reports one Hadith from him in his al Sunan al Kubra which he relates from ‘Abdullah ibn Jafar concerning the Kalimat al Faraj (incantation for salvation).
A number of scholars have praised him. Al Dhahabi said:
He has very few narrations and fatwas despite his truthfulness and lofty status.
Hassan al Muthanna was a devout worshipper, ascetic, and Faqih, who would constantly remain in supplication.
He underwent many trials, amongst them is what he endured alongside his uncle, Sayyidina Hussain radiya Llahu ‘anhu, and the other lanterns from the Ahlul Bayt at Karbala’. Also the attempt of Hajjaj ibn Yusuf al Thaqafi to make him appoint his uncle, ‘Umar al Atraf ibn ‘Ali ibn Abi Talib, also as a custodian of the endowments of ‘Ali radiya Llahu ‘anhu, which he refused to consent to, taking the case before ‘Abdul Malik who assisted him against Hajjaj.
Hassan al Muthanna rahimahu Llah passed away in the year 97 A.H after having led a spiritually prosperous life, replete with knowledge, good deeds, and kindness.
Sayyidah Fatimah bint Hussain rahimaha Llah and Sayyidina Hassan al Muthanna rahimahu Llah were blessed with fragrant roses from their union, the first of whom we will discuss under the next heading.
 I have sourced much of the information in this biography of Hassan al Muthanna rahimahu Llah from the priceless work published by Mabarrat al Al wa al Ashab, authored by ‘Ali ibn Hamd al Tamimi, titled, Hassan al Muthanna and his son, ‘Abdullah al Mahd—A glimpse into their noble lives. [The book has been translated into English by the Mahajjah Research Institute, and is available to download on www.mahajjah.com.]
 Fatwa: Religious edicts. Plural: Fatawa.