Complex sentence: When the two men were alone, Tibaut seized an axe and swung to hit Northup, but Northup defended himself and, though without a weapon, strangled Tibaut to the point of unconsciousness.
Split into simpler sentences: When the two men were alone, Tibaut seized an axe and swung to hit Northup, but Northup defended himself. Without a weapon, he strangled Tibaut to the point of unconsciousness.