Popes, however, although Florence had to a large extent put itself out of reach, have long arms, and gradually--taking advantage of the city's growing discontent with piety and tears and recurring unquiet, there being still a strong pro-Medici party, and building not a little on his knowledge of the Florentine love of change--the Pope gathered together sufficient supporters of his determination to crush this too outspoken critic and humiliate his fellow-citizens.
Events helped the pontiff.

A pro-Medici conspiracy excited the populace; a second bonfire of vanities led to rioting, for the Florentines were beginning to tire of virtue; and the preaching of a Franciscan monk against Savonarola (and the gentle Fra Angelico has shown us, in the Accademia, how Franciscans and Dominicans could hate each other) brought matters to a head, for he challenged Savaronola to an ordeal by fire in the Loggia de' Lanzi, to test which of them spoke with the real voice of God.

A Dominican volunteered to make the essay with a Franciscan.

This ceremony, anticipated with the liveliest eagerness by the Florentines, was at the last moment forbidden, and Savonarola, who had to bear the responsibility of such a bitter disappointment to a pleasure-loving people, became an unpopular figure.

Everything just then was against him, for Charles VIII, with whom he had an understanding and of whom the Pope was afraid, chose that moment to die.
The Pope drove home his advantage, and getting more power among individuals on the Council forced them to indict their firebrand.