Geoffrey Chaucer (; c. 1340s – 25 October 1400) was an English poet and author. Widely seen as the greatest English poet of the Middle Ages, he is best known for The Canterbury Tales. Chaucer has been styled the “Father of English literature”. He was the first writer buried in Poets’ Corner of Westminster Abbey. Chaucer also gained fame as a philosopher and astronomer, composing the scientific A Treatise on the Astrolabe for his 10-year-old son Lewis. He maintained a career in the civil service as a bureaucrat, courtier, diplomat, and member of parliament. Among Chaucer’s many other works are The Book of the Duchess, The House of Fame, The Legend of Good Women, and Troilus and Criseyde. He is seen as crucial in legitimising the literary use of the Middle English vernacular when the dominant literary languages in England were still French and Latin.