In 1821 a minor alteration was made in the Prussian system, by subdividing the thaler into 30 instead of as previously 24 groschen, the former being distinguished from the latter by the title of _silver groschen_. To this Prussian or 14-thaler system Saxony acceded, as did also, in 1848, Mecklenburg and Oldenburg, with many minor differences of detail,--Saxony, for example, dividing the silver groschen into 10 pfennige; Mecklenburg dividing the thaler into 48 schillings of 12 pfennige each; and Oldenburg dividing it into 72 grotens of 5 schwarens each. The gold coin was supplied by the Prussian and Hanoverian 5 and 10-thaler pieces, the Friedrichs _d'or_, a favourite trade coin even in South Germany, and by Spanish _pistoles_ circulating at an equivalence of 4 6-livre thalers. [Sidenote: CONFERENCE OF MUNICH, 1837] The confusion of these various German systems was further increased by the uncertainty and difference which had come to prevail in the unit of weight. In Austria alone there were 2 marks in use, the Vienna mark (= 288.644 grs.), and the Cologne mark (= 243.870 grs.). While in North Germany, and subsequently in the south-west, the Prussian mark (= 233.855 grs.) prevailed. It was as the outcome of a desire to remedy at once the evil condition and confusion of the currency, and the uncertainty as to weight standard, which led to the conference of Munich on 25th August 1837. At that conference, Bavaria, Würtemberg, Baden, Hesse, Darmstadt, and the Free State of Frankfort, adopted the 24-1/2-gulden standard as the standard for their several states. At the same time the Prussian mark (233.855 grms. = half the Prussian pound), was established as the Mint mark for the contracting members. For the divisional coinage (6 and 3-kreutzer pieces) a standard of 27 guldens to the mark was adopted, the details of the various fractional pieces being left to the different states. To this convention Hesse, Hamburg, and the two Hohenzollerns acceded in the following years. This movement of South Germany gave a new impetus to the idea of Mint unification, and led to the General Mint Convention of the States of the Zollverein, agreed upon in full assembly of delegates at Dresden, 30th July 1838, and ratified also at Dresden on the 7th January 1839. The Dresden Convention was practically the first renewed attempt at Mint unification which Germany had seen since 1738. The contracting members to this general Mint convention were Prussia, Bavaria, Saxony, Würtemburg, Baden, Hesse, Saxe-Weimar, Eisenach, Saxe-Meiningen, Saxe-Altenburg, Saxe-Coburg and Gotha, Nassau, Schwarzburg-Rudolstadt, Schwarzburg-Sondershausen, Reuss, Reuss-Schleiz, Reuss-Lobenstein, Ebersdorf, and Frankfurt. Briefly, the articles of the convention were as follow:---- "1. The Mint mark of all these contracting states of the Customs Union shall be the Prussian Mint mark = 233.855 grms.