Tiridates III was the son of Khosrov II of Armenia by an unnamed mother, the latter being assassinated in 252 by a Parthian agent named Anak under orders from Ardashir I. Tiridates had one known sibling, a sister called Khosrovidukht and was the namesake of his paternal grandfather, Tiridates II of Armenia. Anak was captured and executed along with most of his family, while his son, Gregory the Illuminator, was sheltered in Caesaria, in Cappadocia. Being the only surviving heir to the throne, Tiridates was quickly taken away to Rome soon after his father’s assassination while still an infant. He was educated in Rome and was skilled in languages and military tactics; in addition he firmly understood and appreciated Roman law. The Armenian historian Movses Khorenatsi described him as a brave and strong warrior who participated in the battles against enemies. He personally led his army to victories in many battles.