Complex sentence: But it is his family that has made the biggest mark on the traditional music scene, his daughter Mairéad Ní Mhaonaigh is the lead and founding member of internationally recognised group Altan.
Split into simpler sentences: But it is his family that has made the biggest mark on the traditional music scene. His daughter Mairéad Ní Mhaonaigh is the lead and founding member of internationally recognised group Altan.