In Prussia and several other northern German states, the Vereinsthaler was the standard unit of account, divided into 30 Silbergroschen, each of 12 Pfennig.
These states issued Vereinsmünze (union coinage) worth 1 and 2 Vereinsthaler, or 13⁄4 and 31⁄2 gulden.
Following German unification in 1871, the Goldmark was introduced in 1873 at a rate of 3 mark = 1 Vereinsthaler.
Consequently, the new 10 pfennig coins were equivalent to the old Groschen of northern Germany and this became a nickname for the denomination.
Unlike subsidiary silver coins of the goldmark with a legal tender limit of 20 marks, all silver 3-mark Vereinsthalers issued before 1871 enjoyed unlimited legal tender status even after the switchover to the gold standard.