Complex sentence: It is believed to be the site where the Transfiguration of Christ took place, an event in the Gospels in which Jesus is transfigured upon a mountain and speaks with Moses and Elijah.
Split into simpler sentences: It is believed to be the site where the Transfiguration of Christ took place. An event in the Gospels in which Jesus is transfigured upon a mountain and speaks with Moses and Elijah.