William Butler Yeats was an Irish poet, playwright, and one of the foremost figures of 20th-century literature. He was awarded the Nobel Prize in Literature in 1923 for his works which were inspired by Irish folklore and mythology. Yeats is widely considered to be one of the greatest poets of the English language. His most famous works include 'The Lake Isle of Innisfree, ' 'The Wild Swans at Coole, ' and 'When You Are Old.' He is also remembered for his poem 'Easter 1916, ' which commemorates the Easter Rising of that year.