By who and how was Imam Sajjad a.s martyred

Martyrdom of Imam (a.s):

The calm and peaceful life of the Imam was not to be tolerated by the Ummayad's cruel regime. They realized that the Imam was succeeding in his mission of spreading the message of his father Hussain (AS). The Syrian monarch Walid Ibn Abdul Malik had him poisoned. Imam a.s was poisoned by al-Walid ibn `Abdil-Malik ibn Marwan after thirty-five years of Imamate. He died in Madina on the 25th of Muharram 95 Hijri. His eldest son Muhammad Ibn Ali al Baqir arranged the burial and laid him to rest in the grave yard of Jannatul Baqi beside his uncle Imam Hasan (AS).