Complex sentence: Rhadamistus was one of the sons of King Pharasmanes I of Iberia and his wife, an unnamed Armenian Princess of the Artaxiad Dynasty, being the daughter of the Artaxiad Armenian monarchs Tigranes IV and his sister-wife Erato.
Split into simpler sentences: Rhadamistus was one of the sons of King Pharasmanes I of Iberia. His mother was an unnamed Armenian princess of the Artaxiad dynasty, who was the daughter of the Artaxiad Armenian monarchs Tigranes IV and his sister-wife Erato.