Aids - a Term of Medieval Finance
Aids were part of the service due to a lord from his men, and appear to have been based upon the principle that they ought to assist him in special emergency or need. An article from the 1911 Encyclopedia.
A Comparative Chronology of Money
Part of a larger multi-page chronology by Roy Davies and Glyn Davies, this and the next four pages provide brief entries on significant events in the history of money.
Jim's Medieval Coins
A very nice display of 21 medieval coins, primarily French, is accompanied by informative historical background by Jim Mason. Included are coins issued by royal mints, ecclesiastical coins, crusader coins, and more. Fascinating and fun.
Medieval Sourcebook: Economic Life
Useful source of primary documents concerning trade and commerce, coinage, industry, contracts, tolls, and many other economic factors, by Paul Halsall at Fordham University.
Money and Coinage
Overview of coins used in Elizabethan England -- what they're made of, what they're called, and how they're spent, at the Compendium of Common Knowledge.
Money and Coins in Wales
Very brief but informative overview of possible coin production in Wales in medieval times and its later history. Part of a site promoting the book A history of money by Glyn Davies.