Derwent
Derwent Coleridge was the poet's third son. Born September 14th, 1800, the boy maintained a friendly relationship with many of his father's literary friends, including William Wordsworth and Robert Southey. After studying at St. John's College, Cambridge, Derwent embarked on a career as a scholar and professor, becoming accomplished in both fields. Although he had a strained relationship with his father, later in the elder Coleridge's life Derwent assisted him with editing and publishing his work. He died March 23, 1883.
The subtitle to the poem, "Lesson For a Boy," is purposely directed to Derwent.
The Speaker/ S. T. Coleridge
At the close of the poem, the poet references himself to express his love for his son, Derwent. Although perhaps idiosyncratic, Coleridge's poetry is often directed to real-life subjects and usually hints at or outright states his relationship to them.