Simplify the following text for a Grade 6 native English-speaking person.
Original: He vehemently preached against the moral corruption of much of the clergy at the time , and his main opponent was Rodrigo Borgia , who was Pope Alexander VI from 1492 , through to Savonarola 's death , in 1498 .
Simplified: Savonarola was a priest but he preached against the moral corruption of the clergy and the Church of Rome . His main enemy was Pope Alexander VI .