The Deutsche Mark (DEM, DM) or German mark was the official currency of West Germany and, from 1990 onwards, all of unified Germany. It was first issued under Allied occupation in 1948 replacing the Reichsmark, and served as the Federal Republic of Germany's official currency from its founding the following year until 1999, when the Mark was replaced by the euro; its coins and banknotes remained in circulation, defined in terms of euros, until the introduction of euro notes and coins in early 2002. The Deutsche Mark ceased to be legal tender immediately upon the introduction of the euro—in contrast to the other eurozone nations, where the euro and legacy currency circulated side by side for up to two months. However, DM coins and banknotes continued to be accepted as valid forms of payment in Germany until 28 February 2002. The Deutsche Bundesbank has guaranteed that all DM in cash form may be changed into euros indefinitely, and one may do so at any branch of the Bundesbank and banks worldwide. From time to time, some merchants hold promotions where Deutsche Marks are accepted as payment. On 31 December 1998, the European Central Bank (ECB) fixed the irrevocable exchange rate, effective 1 January 1999, for DM to euro as DM 1.95583 = one euro. One Deutsche Mark was divided into 100 Pfennig.