Early Life and Monastic Formation
Arsenius was born in Tver and entered monastic life in his youth at the Kiev Caves monastery, where he received his tonsure and monastic training. According to his vita, he stood out among the brethren for his strictness in keeping his monastic vows, his knowledge of the Church typikon, his study of Holy Scripture, and his love for work.
He served as archdeacon under Metropolitan Cyprian of Kiev. When the Metropolitan was absent, Arsenius governed the administration of the Kiev metropolitanate, a role that reflected the trust placed in him.