Final answer:
Girolamo Savonarola was known for attempting to reform the corrupt Catholic Church from within and for opposing the secular art and culture, exemplified by the Bonfire of the Vanities, before his subsequent execution by the Pope.
Step-by-step explanation:
Girolamo Savonarola was a Dominican friar and preacher who, during the Renaissance, sought to reform the Catholic Church from within before he was ultimately executed. The most important things he did included his attempts to restore clerical morality and his vehement opposition to the secular art and culture of the time, famously culminating in the Bonfire of the Vanities, where he encouraged the burning of items associated with moral corruption and vanity. Savonarola's influence was short-lived, as he was excommunicated and executed by the order of Pope Alexander VI, yet his actions presaged the wider Reformation movements that would later sweep across Europe.