Simplify the following text for a Grade 8 native English-speaking person.
Original: Jean DÃ sirÃ Gustave Courbet ( 10 June 1819 â `` 31 December 1877 ) was a French painter who led the Realist movement in 19th-century French painting .
Simplified: Jean DÃ sirÃ Gustave Courbet ( 10 June 1819 â `` 31 December 1877 ) was a French painter . He was the leader of the Realist movement in 19th-century French painting .