Complex sentence: After leaving Santo Domingo the fleet hit hard weather and 400 men were lost, Narvaez made it to the coast of Texas, and made an inland expedition, but he drowned when trying to sail back to Cuba on rafts.
Split into simpler sentences: After leaving Santo Domingo the fleet hit hard weather and 400 men and were lost. Narváez made it to the coast of Texas, and made an inland expedition, but he drowned when trying to sail back to Cuba on rafts.