Complex sentence: Bourgmont assembled 200 of the Apache chiefs and harangued them on the need for peace among all tribes and implored them to allow Frenchmen to pass through their lands enroute to the Spanish settlements in New Mexico.
Split into simpler sentences: Bourgmont assembled 200 of the Apache chiefs and discussed the need for peace among all tribes. He implored them to allow the French traders to pass through their lands enroute to the Spanish settlements in New Mexico.