Complex sentence: He entered the order of Buddhist monks as a novice at the Asgiri Maha Vihara on July 21,1945, and received his higher ordination Upasampada at the historic "Mangala Upostagara" in Asgiri Maha Viharaya on June 12,1951 at the age of 21.
Split into simpler sentences: He entered the order of Buddhist monks as a novice at the Asgiri Maha Vihara on July 21,1945. He received his higher ordination Upasampada at the historic "Mangala Upostagara" in Asgiri Maha Viharaya on June 12,1951 at the age of 21.