Overview
Lord Weary's Castle, Robert Lowell's second book of poetry, won the Pulitzer Prize for Poetry in 1947 when Lowell was only thirty. Robert Giroux, who was the publisher of Lowell's wife at the time, Jean Stafford, also became Lowell's publisher after he saw the manuscript for Lord Weary's Castle and was very impressed; he later stated that Lord Weary's Castle was the most successful book of poems that he ever published.
Book title
In a note before the first poem of the book, Lowell states that the title of the book was derived from "an old ballad." More specifically, in Frank Bidart's notes to Lowell's Collected Poems, Bidart writes that the title comes from "the anonymous Scottish ballad 'Lamkin.'" Bidart goes on to explain that in the ballad's narrative, "Lord Weary refuses to pay the stonemason Lamkin for building his castle; in revenge for this betrayal, Lambkin kills Weary's wife and child." Bidart does not offer any explanation as to how the story of Lamkin and Lord Weary's castle relates to the content of Lowell's book.
However, in a review of the book that appeared in Poetry magazine, the critic Austin Warren offered the explanation that the book's title implied that "disaster is befalling the house, and the household, of aristocratic (Calvinist, capitalist) New England, which has failed to pay its moral bills to the 'lower order,' its instruments."
From Wikipedia (CC BY-SA 4.0).