Complex sentence: Alexander spent two years at the head of that commission, headquartered in the coastal village of Greytown (now San Juan de Nicaragua) and completed the work to the satisfaction of the two governments, returning to the U.S. in October 1899.
Split into simpler sentences: Alexander spent two years at the head of that commission, headquartered in the coastal village of Greytown (now San Juan de Nicaragua). He completed the work to the satisfaction of the two governments and returned to the U.S. in October 1899.