Complex sentence: Seán's aunt Teresa was also an accomplished musician playing accordion and piano on the music circuit in the 1950s, his aunt Mary (Sister Kevin presentation order) was a teacher of music in the convent school in Dingle, County Kerry.
Split into simpler sentences: Seán's aunt Teresa was also an accomplished musician playing accordion and piano on the music circuit in the 1950s. His aunt Mary (Sister Kevin of the Presentation Order of nuns) was a teacher of music in the convent school in Dingle, County Kerry.