Simplify the following text for a Grade 11 native English-speaking person.
Original: The site flourished in the Preclassic and Classic periods , from the 9th century BC through to at least the 10th century AD , and was an important center of commerce , trading with Kaminaljuyu and ChocolÃ .
Simplified: The site was inhabited the during the Preclassic and Classic periods , from the 9th century BC through to at least the 10th century AD .