We read Endymion with a sharp awareness of its role in the fashioning of Keats. He himself described it as a rite of passage: a “test, a trial of my Powers of Imagination and chiefly of my invention [. . .] by which I must make 4000 Lines of one bare circumstance and fill them with Poetry”; a “[leap] headlong into the Sea” (KL 1.169-70, 374). For most readers, the thrill and tedium of reading Endymion - and the mixture of affection and irritation one feels for it - are linked to this sense of it as a young poet's testing ground: the biographical figure seems revealed in his preciosity, his ambition, his absorption, his overweening love of “fine Phrases” (KL 2.139), and his trying lapses of taste and judgment. The most influential analyses have acknowledged its critical place in Keats's poetic development: “In working out the destiny of his hero,” writes Stuart Sperry, Keats “was in fact working out his own.”