Complex sentence: First, Norris tried to merge Woolwich Arsenal with Fulham (he was a director of both clubs at the time), but when that was blocked by the Football League, Norris abandoned the merger and looked to move Arsenal elsewhere.
Split into simpler sentences: First, Norris tried to merge Woolwich Arsenal with Fulham (he was a director of both clubs at the time). When that was blocked by the Football League, Norris abandoned the merger and looked to move Arsenal elsewhere.