Most countries have some sort of system - standard - for making sure that the content of silver is represented truthfully. Because pure silver is too soft, it is usually alloyed with other metals, typically copper, to give it strength. In the US, for example, all pieces marked "sterling" must be .925 fineness (92.5% by weight of silver and 7.5% by weight of other metals, usually copper).
In 1810 after Napoleon's defeat, the Austrian Empire was divided into three distinct groups: The German-Slavonian lands (Slavonia), the Lombardo-Venetian Kingdom, and the Hungarian Kingdom. Each region had a different standard for silver.
In around 1886 a law was passed that set a common silver standard for all three regions. Under that law, four standards were set for silver, using the head of goddess Diana with a crescent moon. The standard is indicated by the shape of the cartouche and the numeral inside. See below the four silver marks courtesy of http://www.925-1000.com/. In the order they appear:
1= 1st standard .950
2= 2nd standard .900
3= 3rd standard .800
4= 4th standard .750
The letter indicates the city, with the letter "A" for Vienna.
Beginning in 1925 the hallmarks were changed from the head of the goddess Diana to bird heads.
One of the finest Austrian silversmiths of the late 19th century who fulfilled numerous commissions for the Austrian Royal Family was J.C. Klinkosch. See below a mirror by Klinkosch, circa 1890, in the rococo style having the crest, coat of arms and coronet of Prince Maximilian Egon II of Furstenburg and his wife nee Countess Emma
Schonborn-Buccheim. Image courtesy of MS Rau Antiques, New Orleans, LA http://www.rauantiques.com/.
DID YOU KNOW THAT in 1954 the first standard was reduced to .925 fineness - same as the standard for sterling.