Background of the poem "It is a Beauteous Evening, Calm and Free"

In 1790, William Wordsworth visited Calais, France. It was then that he met Annette Vallon. There a love relationship develops between them. Then in 1792, their illegitimate child Caroline was born. Caroline grew up with her mother, Annette Vallon. In 1802 Wordsworth and his sister Dorothy went to Calais to visit Annette Vallon. They stayed there for some time. One evening Wordsworth, his sister Dorothy, his lover Annette Vallon, and their daughter Caroline went for a walk on Calais beach. The poet writes this sonnet describing the calm and beautiful atmosphere of that evening.