During the First World War such money was produced by the warring nations of Europe. In Germany, where 635,000 allied prisoners were confined at the end of the war, it was called _Gefangenenlagergeld_; in France, with the greatest number of German war prisoners (400,000), it was known as _monnaies des camps de prisonniers_. In Germany production reached tremendous amounts and resulted in almost unbelievable varieties, far surpassing the needs dictated by war economy and military policy. Röttinger’s catalogue of German internment camp money lists about 1360 different places of issue and authorities competent to issue such money. There were thousands of types and varieties. All kinds of material were used and all types of style imaginable were represented. From these facts another motif comes to light which prompted that mass production of war prisoner money. Apparently this new type of currency quickly attracted the attention of numismatists, first in the lands of its origin, then in the adjacent neutral countries, and later in the entire world. The interest of collectors and students once awakened was soon exploited by the German government through a mass export of complete sets of prisoner currency to foreign countries. Thus a means was provided of obtaining valuable and badly needed foreign exchange for a worthless kind of currency. In fact it was a practically worthless kind of money, worthless even from the numismatic point of view. For the almost innumerable varieties impaired the collector’s interest who could not entertain any hope ever to obtain a complete collection. While Germany continued this practice for the duration of the war, in line with her general inflationary policy, Austria-Hungary seems to have kept the issuance of her war prisoner money within the limits of the actual war needs.