Complex sentence: The 4th Brigade moved up to the line to relieve the 2nd and 3rd Brigades and would remain there until the division was withdrawn to a training area in late October, following the relief of II ANZAC Corps by the Canadian Corps.
Split into simpler sentences: The 4th Brigade moved up to the line to relieve the 2nd and 3rd Brigades. It would remain there until the division was withdrawn to a training area in late October, following the relief of II ANZAC Corps by the Canadian Corps.