Complex sentence: Before long, Hassen was fighting professional bouts in Brisbane and Townsville and then to Sydney, where he trained under Ern McQuillan, who coached many of Australia's national boxing champions of the era.
Split into simpler sentences: Before long, Hassen was fighting professional bouts in Brisbane and Townsville. And then to Sydney, where he trained under Ern McQuillan, who coached many of Australia's national boxing champions of the era.