Complex sentence: Percy Aldridge Grainger (1882--1961) was an Australian-born composer, arranger and pianist, who played a prominent role in the revival of interest in British folk music in the early 20th century.
Split into simpler sentences: Percy Aldridge Grainger (1882--1961) was an Australian-born composer, arranger and pianist. In the course of a long and innovative career he played a prominent role in the revival of interest in British folk music in the early years of the 20th century.