To answer this question, one need to have a look to that special period of early history of Islam. Imam Hassan, as the second Imam after his father Imam Ali, had a very difficult relation with Moaavieh, the governer of Shaam - who was appointed to this position by second Khalifate but resisted his removal by Imam Ali, who he later killed in an assassination. He is famous for his fraudulant governance and his powerful Propaganda - rumores - against his emenies, the most important was Imam Ali and then Imam Hassan. He made rumors that Imam had 300 wives!, while Imam hassan actualy had only four sons and four daugters!
Imam Sadiq S.A. is son of Imam Baqir S.A. Imam Baqir S.A. is son of Imam Sajjad S.A Imam Sajjad S.A is son of Imam Hussain S.A. Imam Hussain S.A. and Imam Hasan S.A. are children of Imam Ali S.A.
Imam hassan had three sons...hazrat Qasim, hazrat Abdullah and Hazrat hasan-e-mussana. Qasim and Abdullah were martyred in the battle of Karbala. Hasan-e-mussana survived,he was a teen at the time, and later married the daughter of Imam Hussain, Fatima Sughra.
Answer I ( Shia version)he was grandson of prophet and son of daughter of prophet and Imam Ali (sa) and brother of Imam Hussain (sa)Answer II ( Sunny Version )Hazrat Hasan (ra ) was Grandson of Prophet Muhammad saw . He was selected caliph after death of his father Hazrat Ali (ra ) . He left khilaphat in favour of Hazrat Amir Muawia (ra) .h
Muhammad Hasan Imam was born in 1946.
Hazrat Hassan (R.A), passed away at the time of Mo'awiah (R.A) (a caliph NOT considered to be a guided one). One of Hazrat Hassan (R.A)'s wife who was a follower of Mo'awiah poisoned Hazrat Hassan (R.A).
Imam Hasan [AS] who was poisoned by Muaiwaya [LA]. Imam Hussein [AS] who was martyred in Karbala. And Mosen [AS] who was martyred due to Umar's bad treatment of Bibi Fatima Al-Zahra [AS].
Babul Hawaej is a title of Hazrat Ghazi Abbas (A.S.) , He was not the IMAM, But Hazrat Ghazi Abbas was the Companion and Brother of Hazrat Imam Hussain (A.Z.). Also Hazrat Ghazi Abbas (A.S.) was the General of the Army of Hazrat Imam Hussain (A.S.)
There is no historical record or evidence to suggest that Janabe Kubra (Hazrat Fatimah Kubra) was married to Hazrat Qasim, the son of Imam Hasan. Janabe Kubra was known for her piety and knowledge, while Hazrat Qasim was a young martyr in the Battle of Karbala.
Imam Hasan S.A. and Imam Hussain S.A.
Imam Hasan S.A. and Imam Hussain S.A. from Fatima S.A. daughter of prophet.
The Sword of 1st Hazrat Imam ALI (A.S) which was came from Heaven and was transfer to 3rd Imam Hazrat Imam HUSSAIN (A.S) by His father Hazrat ALI (A.S). After Imam HUSSAIN (A.S) was killed in the battle of Karbala it was taken back to the Heaven. When 12th Imam Mohammad Mahdi (A.S) (ALLAH knows) will reappear the sword (zulfiqar) will be shining in his hand Insha ALLAH.
They both were step brothers... And Imam HUSSAIN was very attached to Hazrat ABBAS....