The famous poet known for the line "I wandered lonely as a cloud" is **William Wordsworth**. This line is from his poem "Daffodils," written in the early 19th century. Wordsworth is regarded as a key figure in the Romantic Movement, emphasizing nature, emotion, and individual experience in his works. "Daffodils" reflects his appreciation for the beauty of nature and its power to uplift the human spirit. The poem describes a scene in which he encounters a field of daffodils, leading to a profound personal reflection and appreciation for life’s simple pleasures.