Complex sentence: The 198th Brigade was independent for six months, and was then assigned to 54th (East Anglian) Infantry Division; after the division was disbanded at the end of 1943, it became an administrative headquarters for lines of communications units.
Split into simpler sentences: The 198th Brigade was independent for six months and was then assigned to 54th (East Anglian) Infantry Division. After the division was disbanded at the end of 1943, it became an administrative headquarters for lines of communications units.