similar marine corps - the Infantería de Armada (Navy Infantry) in 1537 but, being from a non English-speaking country, that corps are hardly likely to be the source of the phrase. The Duke of York's men were soldiers who had been enlisted and trained to serve on-board ships. The recruits were considered green and not on a par with hardened sailors, hence the implication that marines were naive enough to believe ridiculous tales, but that sailors weren't. Such a tall tale is often quoted as the source of this phrase. It is said King Charles II made a remark to Samuel Pepys in which he mocked the marines' credulity in their belief in flying fishes. That's a nice story, but it has been shown to be a hoaxthat was perpetrated in the 1900s by the novelist W. P. Drury - a retired Lieutenant Colonel of the Royal Marines.

Most of the early citations give a fuller version of the phrase - "You may tell that to the marines, but the sailors will not believe it". This earliest reference I can find to it that uses the short version that is used today comes from the transcription of a journal that was written by John Marshall Deane, a private in the Foot Guards. His journal was written in 1708 and was transcribed and printed in 1846, under the title of A Journal of the Campaign in Flanders. The preface, which was the work of the transcriber rather than Deane and so must be dated as 1846 rather