Imam Sajjad ( Ali ibn Husayn entitled Zayn al-abidin and Sajjad ) was the son of the third Imam , and his wife , the queen among women , the daughter of Yazdigird the king of Iran . He was the only son of Imam Husayn to survive ,for his other three brothers Ali Akbar , aged twenty-five , five year old Ja'far and Ali Asghar ( or Abdullah ) who was a suckling baby , were martyred during the event of Karbala . The Imam had also accompanied his father on the journey |