Complex sentence: Ambagai was captured by the Tatars while he came to deliver his daughter as a bride to the Tatar confederacy, and was given to the Jurchens of the Jin Dynasty, who cruelly executed him.
Split into simpler sentences: Ambagai was captured by the Tatars while delivering his daughter for marriage into the Tatar confederacy. He was handed over to the Jurchens of the Jin Dynasty, who cruelly executed him.