In 1816, Keats met a circle of friends in London who shared his love of poetry. Among them was Leigh Hunt, the English son of American-born parents who was a crucial influence and supporter of Keats' early work, and Percy Bysshe Shelley, another young Romantic poet. Their encouragement of his poetry helped convince Keats that he could make a career as a writer.
In December 1816 he informed his guardian Richard Abbey that he was leaving medicine for good to concentrate on poetry. Abbey, who prized practical business over esoteric arts, was furious, and the two had a falling-out. Abbey never embraced his adopted son's chosen profession. When Keats gave him a copy of his first poetry collection, he responded, quite nastily, "Well, John, I have read your book, & it reminds me of the Quaker's Horse which was hard to catch, & good for nothing when he was caught - So, Your Book is hard to understand & good for nothing when it is understood." Like Samuel Taylor Coleridge's willing suspension of disbelief, negative capability was a Romantic ideal that allowed man to partake in the ineffable qualities captured only in poetry.
In the summer of 1818, Keats embarked on a six-week walking tour of England and Scotland with his friend Charles Armitage Brown. Keats went on the holiday with some reservations - his youngest brother Thomas, with whom he was very close, was ill with tuberculosis, then known as consumption. Keats was reluctant to leave him, but doctors assured him that Thomas would survive at least until his return. Keats spent the summer and fall touring, caring for Thomas and working on his first long poem, Endymion. He finished Endymion in late November. Just two weeks later, Thomas died of consumption at the age of 19.