The pfennig ; symbol pf or ₰) or penny is a former German coin or note, which was the official currency from the 9th century until the introduction of the euro in 2002. While a valuable coin during the Middle Ages, it lost its value through the years and was the minor coin of the Mark currencies in the German Reich, West Germany and East Germany, and the reunified Germany until the introduction of the euro. Pfennig was also the name of the subunit of the Danzig mark (1922–1923) and the Danzig gulden (1923–1939) in the Free City of Danzig.