Wiardunek

The Wiardunek (also referred to as wiardunk, czwartak or ferton; German: Viertel,^[1] Latin: ferto) was a Mediaeval Central European unit of mass most widely used in Poland and Germany.^[1] Wiardunek was also used as a unit of account, and as a such as commodity money.

As a unit of mass 1 wiardunek (ca. 49 g) was equivalent to 1/4 of grzywna.^[2] Two ounces made up one wiardunek, and in turn each ounce consisted of two lots.

As a unit of currency, the wiardunek was introduced probably around 14th century, first in Bohemia and then in other Central European states.^[2] This usage followed the same scheme as for other commodities, that is 1 wiardunek of pure silver was equivalent to 1/4 of grzywna, which in turn was composed of 64 groschen.^[2] This usage was true regardless of changes in overall weight of grzywna, which was the basic unit of mass in this system.^[3]