Complex sentence: During the Edo period, Aizu was a feudal domain known as and part of Mutsu Province; the area once was part of Iwase Province in the 700s and, before the prefectural system, Iwashiro Province.
Split into simpler sentences: During the Edo period, Aizu was a feudal domain known as. It was part of Mutsu Province; the area once was part of Iwase Province in the 700s and, before the prefectural system, Iwashiro Province.