The big problem with money created by the government is that those who run the government always face the temptation to create more money and spend it. Whether among ancient kings or modern politicians, this has happened again and again over the centuries, leading to inflation and the many economic and social problems that follow from inflation. For this reason, many countries have preferred using gold, silver, or some other material that is inherently limited in supply, as money. It is a way of depriving governments of the power to expand the money supply to inflationary levels. Gold has long been considered ideal for this purpose, since the supply of gold in the world usually cannot be increased rapidly. When paper money is convertible into gold whenever the individual chooses to do so, then the money is said to be "backed up" by gold. This expression is misleading only if we imagine that the value of the gold is somehow transferred to the paper money, when in fact the real point is that the gold simply limits the amount of paper money that can be issued.