Complex sentence: After Cassandra told him of the prophecy, stating that a boy, born on the winter solstice, who has seen both darkness and light, would vanquish an evil, Duncan was returned to his father, Ian Macleod.
Split into simpler sentences: After Cassandra told him of the prophecy, stating that a boy, born on the winter solstice, who has seen both darkness and light, would vanquish an evil. After this, Duncan was returned to his father, Ian Macleod.