Complex sentence: These were abandoned and the soldiers withdrew back to the Philippines in order to re-concentrate their military forces because of a threatened invasion by the Japan-born Ming-dynasty loyalist, Koxinga, ruler of the stronghold of Tungning.
Split into simpler sentences: These were abandoned and the soldiers withdrew back to the Philippines. They withdrew in order to re-concentrate the military forces because of a threatened invasion by the Japan-born Ming-dynasty loyalist, Koxinga, ruler of the stronghold of Tungning.