At a time when length is the fashion for historical novels, it’s a pleasure to read Denise Mina’s elegant novella. As with Rizzio, her previous venture in this genre, her economy pays off. Everything moves quickly and it’s intensely dramatic like a Shakespearean tragedy or history play. It takes no more time to read than you would spend in the Stratford theatre.

The story is set in Florence in the last decade of the 15th century. In Italy it is famous. Students of the politics of the Italian Renaissance will know it as well as foreign students of Scottish history will know the grim politics of Queen Mary’s reign and the murder of Rizzio in the Palace of Holyroodhouse. But for many readers here it will be new ground; many will buy it simply because they have the good taste to buy anything Denise Mina writes.

It's the story of a Dominican friar, Girolamo Savonarola, and the religious revolution he inspired and led in Florence in the last decade of the century. Florence was rich and splendid, the city of the Medici, of great painters, architects and writers, governed then by Lorenzo the Magnificent. But it was also corrupt and debauched, a city of bankers and usury, Jews among the money-lenders. The poor were very poor, ripped off by the rich. It was all for Savonarola a negation of God. He was a man sent by God. God spoke to him. He was like an Old Testament Prophet, Elijah or Jeremiah. He was inspired. The words he spoke were the words of God. He prophesied deaths – of Lorenzo and the Pope – and the deaths happened. He said there would be a French invasion of Italy – a cleansing invasion – and so it came about. The people were mad for him. He can be seen as a forerunner of Martin Luther and our John Knox. His revolution was cultural as well as religious: Botticelli stopped painting nudes, the inns were closed and the gambling dens shut. Meanwhile, the Jews were persecuted. Savonarola was fiercely anti-Semitic – according to him, the Jews were “Christ-killers”.

Denise Mina is bold as well as clever. The first chapter opens near the end of the story when, after torture, Savonarola shuffles into the Great Hall of the Palazzo della Signoria, a broken man. He is ready to confess in public: he has lied, God has never spoken to him; he is no prophet, only a man who has lied to gain power. It is as horrible as a Stalinist show trial. Mina has taken a risk, but it works. Oddly, it makes everything that we learn more dramatic, more horrible. And why not? We know how Macbeth will end even before the witches speak. This first scene wins our regard, our sympathy for a man whom, otherwise, one might see only as a mad fanatic. There’s a second scene too which gives Savonarola a normal humanity; one in which, as a young man before he is a friar or hears God speak, he receives a very natural, normal but painful and humiliating rebuff. It is very cleverly done.

It is impossible not to feel sympathy for Mina’s Savonarola, respect too, But he is a fanatic, a man with no feeling for ordinary, sinful humanity. He is a reformer who is also a destroyer, a man of God like an Ayatolla or a revolutionary like Robespierre or or Chairman Mao. One remembers that the Dominican friars staffed the Inquisition in Rome and Spain.

This little book is beautifully done. One has sympathy for Savonarola – he is heroic and his end is appalling. But one would no more care to live in his Florence than in Calvin’s Geneva or Mau’s China. Still this is a remarkable, moving and thought-provoking book. I often dislike fiction written in the present tense. Denise Mina makes it acceptable, however, more than acceptable indeed. It’s a rare achievement.

Three Fires, by Denise Mina, Polygon. 136pp. £10. Denise Mina is appearing at the Edinburgh International Book Festival on 16 August

Book review: Three Fires, by Denise Mina