Complex sentence: When Cook had first arrived in the islands he was greeted with great honor, as his arrival coincided with the Makahiki, a festival celebrating the yearly harvest while worshipping the Hawaiian deity, Lono.
Split into simpler sentences: When Cook had first arrived in the islands he was greeted with great honor. His arrival coincided with the Makahiki, a festival celebrating the yearly harvest while worshipping the Hawaiian deity, Lono.