Simplify the following text for a Grade 9 native English-speaking person.
Original: Garry Kimovich Kasparov ( , ; born Garry Kimovich Weinstein , 13 April 1963 , Baku , Azerbaijan ) is a Russian ( formerly Soviet ) chess grandmaster , a former World Chess Champion , writer , and political activist , whom many consider the greatest chess player of all time .
Simplified: Garry Kasparov ( born Baku , Azerbaijan , 13 April 1963 ) is a Russian chess grandmaster and political activist . He was born with the name Garry Weinstein , and was the World Chess Champion from 1985 to 2000 .