Dante Alighieri (c1265 - 1321). Durante di Alighiero degli Alighieri, commonly known by his pen name Dante Alighieri or simply as Dante, was an Italian poet. His Divine Comedy, originally called Comedìa and later christened Divina by Giovanni Boccaccio, is widely considered the most important poem of the Middle Ages and the greatest literary work in the Italian language. In the Late Middle Ages, most poetry was written in Latin, making it accessible only to the most educated readers. In De vulgari eloquentia, however, Dante defended the use of the vernacular in literature. He would even write in the Tuscan dialect for works such as The New Life and the Divine Comedy; this highly unorthodox choice set a precedent that important later Italian writers such as Petrarch and Boccaccio would follow. Dante was instrumental in establishing the literature of Italy, and his depictions of Hell, Purgatory and Heaven provided inspiration for the larger body of Western art. He is cited as an influence on John Milton, Geoffrey Chaucer and Alfred Tennyson, among many others. In addition, the first use of the interlocking three-line rhyme scheme, or the terza rima, is attributed to him. He is described as the father of the Italian language, and in Italy, he is often referred to as il Sommo Poeta. Dante, Petrarch, and Boccaccio are also called the tre corone of Italian literature. Dante was born in Florence, Republic of Florence, present-day Italy. The exact date of his birth is unknown, although it is generally believed to be around 1265. This can be deduced from autobiographic allusions in the Divine Comedy. Its first section, the Inferno, begins, Nel mezzo del cammin di nostra vita, implying that Dante was around 35 years old, since the average lifespan according to the Bible is 70 years; and since his imaginary travel to the netherworld took place in 1300, he was most probably born around 1265. Some verses of the Paradiso section of the Divine Comedy also provide a possible clue that he was born under the sign of Gemini: As I revolved with the eternal twins, I saw revealed, from hills to river outlets, the threshing-floor that makes us so ferocious. In 1265, the sun was in Gemini between approximately May 11 and June 11. Giovanni Boccaccio described Dante's appearance and demeanor as follows: the poet was of middle height, and in his later years he walked somewhat bent over, with a grave and gentle gait. He was clad always in most seemly attire, such as befitted his ripe years. His face was long, his nose aquiline, and his eyes big rather than small. His jaws were large, and his lower lip protruded. He had a brown complexion, his hair and beard were thick, black, and curly, and his countenance was always melancholy and thoughtful. Dante claimed that his family descended from the ancient Romans, but the earliest relative he could mention by name was Cacciaguida degli Elisei, born no earlier than about 1100. Dante's father, Alighiero or Alighiero di Bellincione, was a White Guelph who suffered no reprisals after the Ghibellines won the Battle of Montaperti in the middle of the 13th century. This suggests that Alighiero or his family may have enjoyed some protective prestige and status, although some suggest that the politically inactive Alighiero was of such low standing that he was not considered worth exiling. Dante's family was loyal to the Guelphs, a political alliance that supported the Papacy and which was involved in complex opposition to the Ghibellines, who were backed by the Holy Roman Emperor. The poet's mother was Bella, likely a member of the Abati family. She died when Dante was not yet ten years old, and Alighiero soon married again, to Lapa di Chiarissimo Cialuffi. It is uncertain whether he really married her, since widowers were socially limited in such matters, but this woman definitely bore him two children, Dante's half-brother Francesco and half-sister Tana. When Dante was 12, he was promised in marriage to Gemma di Manetto Donati, daughter of Manetto Donati, member of the powerful Donati family. Contracting marriages at this early age was quite common and involved a formal ceremony, including contracts signed before a notary. But by this time Dante had fallen in love with another, Beatrice Portinari, whom he first met when he was only nine. Years after his marriage to Gemma he claims to have met Beatrice again; he wrote several sonnets to Beatrice but never mentioned Gemma in any of his poems. The exact date of his marriage is not known: the only certain information is that, before his exile in 1301, he had three children. Dante fought with the Guelph cavalry at the Battle of Campaldino. This victory brought about a reformation of the Florentine constitution.