Complex sentence: Crewmen of the ship were attacked by the Native Americans when they departed the ship, and John Colman was killed, making him what is said to be the first European to be felled by a Native American arrow.
Split into simpler sentences: Crewmen of the ship were attacked by the Native Americans when they departed the ship, and one man, John Colman, was killed. He is reputed to be the first European to be felled by a Native American arrow.