Not surprisingly, the first blackmailers were corrupt politicians, 17th century Scottish chieftains who demanded protection money from local farmers, who refused only at the risk of having their crops destroyed. The ‘mail,’ or payment, was said to be ‘black’ probably because the color black had long been associated with darkness and evil, but it might also have been because payment was usually made in livestock, rather than in silver (which was known as ‘white money’).
The ‘give me two cows or I’ll burn down your farm’ kind of blackmail first appeared in English around 1552, but by the early 1800’s we were using ‘blackmail’ to mean just about any sort of extortion, especially using threats to reveal secrets.
Blackmail
meaning the extortion of money by the use of threats, especially threats to reveal secret or embarrassing information, comes from a now obsolete, sense of “mail” meaning “payment” or “tax.” This “mail” came originally from the Old Norse word “mal,” meaning “agreement,” and exists as a word today only in Scots and some dialects in northern England.