Complex sentence: During the Napoleonic wars, Brown is said to have escaped the galley, and scuttled the ship however, the French, not believing he had assisted them, took him prisoner and sent him to Lorient.
Split into simpler sentences: During the Napoleonic wars, Brown is said to have escaped the galley, and scuttled the ship. However, the French didn't believe he had assisted them and took him prisoner and sent him to Lorient.