Arsacius was a cleric from Tarsus in Cilicia who succeeded John Chrysostom as Patriarch of Constantinople.
Arsacius was born in Tarsus, the brother of Nectarius - another Patriarch of Constantinople.
He was ordained on June 26, 404 in the Church of the Holy Apostles and reigned until November 11, 405. During his reign, a vicious persecution against the followers of John Chrysostom took place.
Arsacius himself was over 80 years old at the time. He was described as "more quiet than a fish" and "more idle than a frog" and it is probable that he was a mere figurehead with little understanding of what went on around him.
His memory is celebrated on the same day - October 11 - as his brother's.