Complex sentence: In the 1970s Slim performed on tours in Europe, both in the UK and at the Montreux Jazz Festival in Switzerlandwhere he was often accompanied by Moses "Whispering" Smith on harmonica.
Split into simpler sentences: In the 1970s Slim performed on tours in Europe, both in the UK and at the Montreux Jazz Festival in Switzerland. He was mostly accompanied by Moses "Whispering" Smith on harmonica.