Invented in Lydia in the 6th century, money was adopted by the Greeks and then passed on to the rest of the Mediterranean world, as it also came into existence in other parts of the world. Not only a tool of economic value, it also quickly became a political tool as well; indeed, the kings, and later the Roman Emperor and European kings minted coins that bore their effigy, thereby indicating the legitimacy of the monarch’s rule. The Greek poleis minted coins that bore the symbol of the polis, thus demonstrating its independence from its neighbors. In the course of the 19th and 20th centuries, when most European kingdoms became republics, the coins and newly invented bills were decorated with portraits of men–and sometimes women–who had an important impact on the country: scientists, philosophers, writers, etc. Thus, on French bills figured Moliere, Voltaire, Antoine de St-Exupery, Marie Curie, etc, who all represented not only what they offered the country, but thus what the country contributed to European culture and civilization.