Complex sentence: After the battle of Talavera the depleted infantry battalions (now re-organised as the 2nd regiment of infantry) were reunited with the cavalry and artillery of the brigade and again made part of IV Corps, now commanded by the newly promoted Marshal Sébastiani.
Split into simpler sentences: After the battle of Talavera, the depleted infantry battalions, now re-organised as the 2nd regiment of infantry, were reunited with the cavalry and artillery of the brigade. The battalions were again made part of IV Corps, now commanded by the newly promoted Marshal Sébastiani.