Dante lived 700 years ago, and information about his life is meagre, so the biographer must look for the man in his work and in the history of his times. Florence - where Dante was born and from which he was banished at the age of 37, never to return - was one of many warring city states in the north of Italy. When it was not attacking or being attacked, it was riven by internal factions; nevertheless, it was prospering as a financial and commercial centre.
Dante peopled his Hell with war lords and speculators and leaders of rival gangs, many of whom he knew personally, and he did not scruple to allot them what he considered punishments to fit the crime. The barrators, those who have misused public funds for private gain - an unhappily familiar sin in our day, says Lewis - are near the bottom of Hell in a lake of boiling pitch.
At the same level, swathed in flames, is Ulysses, punished for his part in getting the Trojan Horse inside the walls of Troy. In his mouth are put some of the most eloquent and inventive words in the whole of the Divine Comedy, which show that Dante was a poet before he was a theologian. His poetic, and dramatic, skills made his fictional or visionary account seem to be the very truth, and his descending circles of perdition the very geography of Hell. Glimpsed in the streets of Verona once, an observer attributed his dark complexion to his bodily experience of the infernal flames.
Lewis brings to our attention the episodes most nearly connected with the poet's life, and views the poet's journey through Inferno, Purgatorio and Paradiso as a voyage of self-discovery and spiritual growth. The Purgatorio is, the poet says, "that second realm where the human spirit purges itself and becomes worthy to ascend to heaven", and the Paradiso leads it to the realisation that it is moved by the same "love that moves the sun and the other stars":
L'amor che move il sole e l'altre stelle.
Dante is guided on his journey by Virgil, who eventually hands over to St Bernard of Clairvaux, but in the background is always the benign presence of Beatrice, first seen by Dante when he was 9 and she was 8. Although they were neighbours and could see each other from time to time, it was nine years before she actually spoke to him.
After this Dante had the first of a remarkable series of dreams, described in his Vita Nuova (New Life) written after Beatrice's death in her 24th year. She had always been unattainable - Dante was betrothed from the age of 11 to Gemma Donati, whom he married eight years later - and death, in the poet's mind, transformed Beatrice from imaginary mistress to spiritual power and intercessor.
At a certain level, the Comedy is Dante's hymn to Beatrice, his adjustment of the Christian scenario to his private mythology; but his aim was to bring his readers from a state of misery to a state of bliss by sharing with them his visions of the Christian revelation.
Lewis interweaves the poetry with the life in a way that leads to some repetition, but he keeps before us the figure of a man who believed that the intellectual must shoulder civic responsibilities, who played his part as soldier and public official and wrote a treatise - De Monarchia - in favour of universal peace, to be secured in a single and universal empire ruled over by a single monarch or emperor. He had a candidate for the job who failed to take action against the Florentines, and Dante had to remain in exile, living in various cities of northern Italy until his death from malaria in 1321. Had it not been for that exile, the Comedy might not have been as powerful as it is.
Douglas Sealy is a translator and critic