Complex sentence: One of the'three kings' of the east (magi, wise men in the Christian Bible) was a Zoroastrian priest named Caspar, whose gift to the infant Jesus was a cask gold, of which of was guardian.
Split into simpler sentences: One of the'three kings' of the east (magi, wise men in the Christian Bible) was a Zoroastrian official named Caspar. His gift to the infant Jesus was a cask gold, of which he was guardian.