Complex sentence: The 17th and 3rd Cavalry brigades assisted the in and south of Halen, which enabled artillery to be brought to the fringe of the village but attacks into cornfields beyond were repulsed with many casualties, some cavalry becoming trapped by wire fences.
Split into simpler sentences: The 17th and 3rd Cavalry brigades assisted the in and south of Halen, which enabled artillery to be brought to the fringe of the village. Attacks into the cornfields beyond were repulsed with many casualties, some cavalry becoming trapped by wire fences.