Complex sentence: Embarrassed, Quetzalcoatl banished himself to the sea, saying he would return one day to get his revenge.Coincidentally, the year he was said to return was remarkably the same year Cortes landed on the shores of Mexico in 1519.
Split into simpler sentences: Embarrassed, Quetzalcoatl banished himself to the sea, saying he would return one day to get his revenge. The year he was said to return coincided with the year Hernán_Cortés landed on the shores of Mexico in 1519.