Complex sentence: The left wing of Ondoher's army was commanded by Adrahil, the Prince of Dol Amroth, the right wing was commanded by Minothar, the captain of Gondor's armies.
Split into simpler sentences: The left wing of Ondoher's army was commanded by Adrahil, the Prince of Dol Amroth. The right wing was commanded by Minothar, the captain of Gondor's armies.