Complex sentence: By September of 2004, there were 8 galleries operating, and the Downtown Art Walk was begun by Bert Green, a month in advance of the opening of his downtown gallery at 5th and Main.
Split into simpler sentences: By September of 2004, there were 8 galleries operating. The Downtown Art Walk was begun by gallery-owner Bert Green, a month in advance of the opening of his gallery at 5th and Main.