When the King of France invaded Italy in 1494, princely states would fall, sending tremors up and down the peninsula. The Medici fled from Florence; the republic sprang back to life; and the French army, occupying the Renaissance city for ten terrifying days, stood on the verge of sacking it. A 'little friar' from Ferrara, Savonarola was alone in knowing how to comfort citizens with his sermons and in urging the King to get out of Florence.

Although the French left a city riven by political factions, the Friar's popular 'party' swiftly prevailed. With Florence at the height of its Renaissance glories, his voice rose above those of all other men. Claiming to be a messenger from God, he attacked evils on all sides - a mercenary Church, the despotism of the Medici, vile political elites, and Pope Alexander VI, Rodrigo Borgia, whose name itself was a byword for brazen corruption. Savonarola foretold a universal 'scourging', but made pleas, above all, for the renewal of Christianity and for the political voice of the people. His struggle turned into a battle for the 'soul' of Florence.

Excommunicated and silenced, Savonarola spurned Rome and began to preach again, retaining the strong support of the city republic. As the Pope and Medicean conspirators closed in on him, five prominent Florentines were beheaded for plotting against the state, further inflaming the passions already rife in the city. After an abortive trial by fire to shame and discredit him, his enemies set siege to his convent, leading to his arrest and trial on trumped-up charges of heresy.

Savonarola mingled the fervour of religion with the ardour of republican politics. Scourge and Fire is the story of his impact on Florence and of the city's spell over him.