The Cologne mark is an obsolete unit of weight (or mass) equivalent to 233.856 grams (about 3,609 grains).
It came to be used as the base unit for a number of currency standards, including the Lübeck monetary system, which was important in northern Europe in the late Middle Ages, and the coinage systems of the Holy Roman Empire, most significantly the 1754 conventionsthaler, defined as 1⁄10 of a Cologne mark.
[2] The Cologne Pfund (2 marks) should not be confused with the Pfund of around 350 grams, 5400 grains, used in the Nuremberg apothecaries' system (Apothekergewicht), and is approximately equal to the old Tower pound (1+1⁄2 marks).
[3]In the late Middle Ages, Portugal used local variants of the marks of Cologne (Colonha) and Troyes (Tria), the first for coinage and precious metals and the second for haver-de-peso (avoirdupois).
[4]In modern times, the Portuguese mark of Cologne drifted towards 229.5 grams.