Where Did the Phrase "Blood Is Thicker Than Water" Come From?

“Where did the phrase ‘blood is thicker than water’ come from?”

You’ve probably heard the saying “blood is thicker than water,” meaning that family ties take precedent over any other relationship, but you may not have realized how long it’s been around. In the Random House Dictionary of Popular Proverbs and Sayings, Gregory Titelman traces its origin back to John Lyndgate’s Troy Book. Lyndgate’s book, a long poem about the history of Troy from its beginnings until the end of the Trojan War, can be found in the Cleveland Public Library’s special collections department, and parts of it can also be found online at archive.org. It was written around 1412 in Middle English, so it’s interesting to have a look at.

Titelman cites a few other early uses of the phrase: A Collection of English Proverbs by John Ray, written in 1670, and Journal of Athabasca Department (which seems to refer to Sir George Simpson’s Journal of Occurrences in the Athabasca Department), written in 1821. Both are available at the Cleveland Public Library, the former in microform and special collections and the latter in the history department. An edition of A Collection of English Proverbs is also available at archive.org.

However, http://www.phrases.org.uk/ claims that “blood is thicker than water” first appeared in Sir Walter Scott’s Guy Mannering; or, The Astrologer, published in 1815. The exact quote where it appeared is "Weel, blude's thicker than water; she's welcome to the cheeses and the hams just the same." 

The Facts on File Encyclopedia of Word and Phrase Origins (3rd Edition) by Robert Hendrickson traces it back even further. According to Hendrickson, the phrase became famous when used by U.S. commodore Josiah Tattnall in 1859. Tattnall came to the aid of the British against the Chinese even though it would violate U.S. neutrality, and gave “blood is thicker than water” as his reason for doing so. However, Hendrickson writes, the phrase is much older than that – it was first recorded in Germany in the 1100s.

Despite whatever you think about family ties, the phrase is scientifically true – blood is indeed thicker than water.