Simplify the following text for a Grade 11 native English-speaking person.
Original: Inspired by Beatle 's music , Grigoryan , while still in high school , started his musical career and in 1983 he formed `` Crematorium '' which gained a reputation throughout the former Soviet Union and begin to perform at concerts all over the country .
Simplified: In 1983 , he formed `` Crematorium '' which gained a reputation throughout the former Soviet Union and begin to perform at concerts all over the country .