Who was the oldest martyr of Karbala?

As probably many of you are aware, at the time of Imam Hussain (a.s.) there was a tragedy event which was/is famous as "Battle-of-Karbala". It is as follow: - www.al-islam.org/the-tragedy-of-karbala But the question which I am looking for, is that who the name of the oldest person of Battle-of-Karbala (as the soldier of Imam Hussain (a.s.)) was who was martyred during the battle.