Complex sentence: By daybreak all the brigade's objectives had been secured, then to the west of the Caen Canal, the 7th Battalion was attacked, by tanks and armoured vehicles from the 21st Panzer Division.
Split into simpler sentences: By daybreak all the brigade's objectives had been secured. To the west of the Caen Canal, the 7th Battalion was attacked by tanks and armoured vehicles from the 21st Panzer Division.