The name and symbols of the political community on the coins that it mints show the close relationship that exists between the right to issue currency and the sovereign authority of a State, which derives directly from the very essence of the coin. All through history, coins have meant more to those in power than a simple means of exchange or an expedient form in which to amass wealth; they have always been an ideal support for spreading the images of rulers far and wide, long before the powerful communications systems we have today came into existence. Thus, coins are extremely useful documents to discover some of the features of the sovereign power of a nation. Here coins are analyzed as points of reference on power, beginning with the earliest known mintages and continuing down thro ugh history until we reach modern nations, where a reflection on the adoption of the euro by the European Union is encouraged.