A Roman silver coin, equal in value to ten ases (deni-ases ). The word was used in France and England for the inferior coins, whether silver or copper, and for ready money generally. Now d ( denarius) stands for money less than a shilling, as £ s. d.
“The denarius ... shown to our Lord ... was the tribute-money payable by the Jews to the Roman emperor, and must not be confounded with the tribute paid to the Temple.” —F. H. Madden: Jewish Coinage, chap. xi. p. 247.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894