Simplify the following text for a Grade 10 native English-speaking person.
Original: Bohuslav MartinÅ ( December 8 , 1890 , PoliÄ ka , Czechia â `` August 28 , 1959 , Liestal , Switzerland ) was a prolific Czech composer of modern classical music .
Simplified: Bohuslav MartinÅ ( born PoliÄ ka , Bohemia , 8 December 1890 ; died Liestal , Switzerland , 28 August 1959 ) was a Czech composer .