Complex sentence: Although Major Beasley, the commander, stated that he could "maintain the post against any number of Indians", the stockade was poorly-defended, and at the time of the attack, the East gate was partially blocked open by drifting sand.
Split into simpler sentences: Although Major Beasley, the commander, stated that he could "maintain the post against any number of Indians", the stockade was poorly defended. At the time of the attack, the East gate was partially blocked open by drifting sand.