Complex sentence: However, he is killed during the Battle of Vittorio Veneto, and so when Cora learns that Mrs Hughes is supporting Ethel, she is persuaded to invite Major Bryant's parents to Downton Abbey.
Split into simpler sentences: However, he is killed during the Battle of Vittorio Veneto. When Lady Cora learns that Mrs Hughes is supporting Ethel, she is persuaded to invite Major Bryant's parents to Downton Abbey.