Simplify the following text for a Grade 7 native English-speaking person.
Original: The first cause of cancer was identified by British surgeon Percivall Pott , who discovered in 1775 that cancer of the scrotum was a common disease among chimney sweeps .
Simplified: British surgeon Percivall Pott was the first to find a cause for cancer . In 1775 , he discovered that cancer of the scrotum was a common disease among chimney sweeps .