Complex sentence: The area to the north is called Ashridge (anciently called Hertoke) and is the region of Wokingham parish which was, until 1844, officially a detached part of Wiltshire.
Split into simpler sentences: The area to the north is called Ashridge (anciently called Hertoke). This is the region of Wokingham parish which was, until 1844, officially a detached part of Wiltshire.