He was the first prominent Livonian to be christened. He was probably baptized around 1191 by a priest called Theoderic. He became an ardent Christian and friend of Albert of Buxhoeveden, Bishop of Riga, who took him 1203-1204 all the way to Rome and introduced him to Pope Innocent III. The Pope was impressed by the converted pagan chief and presented him a Bible. When he returned from travel, his tribe rebelled against him and Caupo helped to conquer and destroy his own former Castle of Turaida in 1212. The castle was rebuilt two years later as a stone castle that is well preserved even today.