Answer: the French Revolution; the death of his brother; and his alienation from Coleridge.
Explanation:By the later part of his career, the poet had grown disillusioned with the values and hopes of Romanticism. He was beset by doubts of the validity of his early beliefs and poems. Many things contributed to this disillusionment: the failure of the French Revolution; his inability to experience the passion of youth; the death of his brother; his alienation from Coleridge; and the inevitable acceptance of life's realities that comes with age.