What was C.S. Lewis's surname-based pen name for his early poetry?

C.S. Lewis used the pen name Clive Hamilton for his early poetry.

Lewis published Spirits in Bondage in 1919 under the name Clive Hamilton. The collection appeared soon after his military service in the First World War and reflects the darker, more skeptical outlook of his early adulthood. He used a pseudonym rather than his familiar initials for this first book.

Lewis later published Dymer in 1926 under the same name. That long narrative poem was issued while he was developing his academic career and before his public reputation as a Christian writer had fully formed.

Readers sometimes confuse Clive Hamilton with Lewis’s nickname, Jack. Jack was the personal name used by friends and associates, not the pen name on these poetry volumes. Lewis’s later nonfiction and fiction were generally published as C.S. Lewis, making Clive Hamilton chiefly associated with his early poetry.