Complex sentence: Papers found on board showed Lieutenant de vaisseau Jean-Jacques-Léonore Daniel had been the commander, and that she was armed with sixteen French 24-pounder carronades, two long 9-pounders, a brass howitzer and four brass 3-pounders.
Split into simpler sentences: Papers found on board showed Lieutenant de vaisseau Jean-Jacques-Léonore Daniel had been the commander. She had been armed with sixteen French 24-pounder carronades, two long 9-pounders, a brass howitzer and four brass 3-pounders.