Complex sentence: It later became a part of the first Active Component/Reserve Component division as one of the three brigades that comprised the 7th Infantry Division, until that division was deactivated in August 2006.
Split into simpler sentences: It later became a part of the first Active Component/Reserve Component division. It is one of the three brigades that used to make up the 7th Infantry Division, until that division was deactivated in August 2006.