Complex sentence: Despite some success, Brady returned to Ireland in 1974 to join the highly influential Irish group Planxty, the band that would subsequently launch the solo careers of Andy Irvine, Liam O'Flynn, Dónal Lunny, and Christy Moore.
Split into simpler sentences: Despite some success, Brady returned to Ireland in 1974 to join the Irish group Planxty. This was the band that was to launch the solo careers of Andy Irvine, Liam O'Flynn, Dónal Lunny, and Christy Moore.