Rabindranath Tagore's Gitanjali, a collection of poems, the most popular work by Rabindranath Tagore, was published in India in 1910. Later, he translated it into prose poetry in English as Gitanjali, Song Offerings, and it was published in 1912 with an introduction by William Butler Yeats. Medieval Indian lyrics of affection gave Tagore's model to the poems of Gitanjali, as well as he composed music for these lyrics. Love is the essential subject, even though some poems are about the internal journey between spiritual longings and earthly desires. More of his imagination is drawn from nature, and the commanding mood is minor-key and muted. This collection helped him win the Nobel Prize in Literature in 1913. However, a few later critics disagreed that it addressed Tagore's best work.