Complex sentence: Acland was grateful for the treatment received when recuperating as a prisoner of war, so much so that following his return to England he challenged a certain Lieutenant Lloyd to a duel when the latter spoke poorly of Americans at a dinner party.
Split into simpler sentences: Acland was grateful for the treatment received when recuperating as a prisoner of war. Upon returning to England he challenged a Lieutenant Lloyd to a duel when the latter spoke poorly of Americans at a dinner party.