Complex sentence: He fought under Arthur Wellesley, 1st Duke of Wellington at the Battle of Vimiera, and later took part in the retreat of Sir John Moore's army to Corunna, and was present at the Battle of Corunna.
Split into simpler sentences: He fought under Arthur Wellesley, 1st Duke of Wellington at the Battle of Vimiera. He later retreated with the rest of Sir John Moore's army to Corunna, and was present at the Battle of Corunna.