German States, 1594 AD., Brunswick-Grubenhagen, Wolfgang and Philipp II, 1/2 Reichstaler diamond shape, in the name of emperor Rudolf II, St. Andreas mine metal, Andreasberg mint reproduction of 1985 AD.

Brunswick-Grubenhagen, Wolfgang and Philipp II (1567-95), in the name of HR emperor Rudolf II, original date 1594 AD., St. Andreas mine metal, Andreasberg mint reproduction of 1985 AD.,
1/2 Reichstaler diamond shape (12 Groschen, "Klippe") (32 x 32 mm / 12,81 g), 0.9999 silver, axes medal alignment ↑↑ (0°), plain edge,
Obv.: ·WOLF·ET·PHIL·D:G·DV-BRVN·E·LVNE· / 1985 - 999,9 , helmeted arms of Brunswick Luneburg, actual date and silver content below.
Rev.: RVDOLPHVS·II·D· - ·G·ROM·IM·SEM·AV / IZ / 9 - 4 , Saint Andrew, nimbate, holding cross, orb containing value IZ (= 12) at center, date flanking, flag and heart on crossed hammers below.
cf. Müseler 10.1/2 ; - Welter 534 .

The Principality of Grubenhagen was a subdivision of the Duchy of Brunswick-Lüneburg, ruled by the Grubenhagen line of the House of Welf from 1291. It is also known as Brunswick-Grubenhagen. The principality fell to the Brunswick Principality of Lüneburg in 1617; from 1665 the territory was ruled by the Calenberg branch of the Welf dynasty.
The principality was located on the southwestern edge of the Harz mountain range in present-day South Lower Saxony. It included two separate territories, one around the town of Einbeck with Grubenhagen Castle, and another domain around the towns of Osterode and Duderstadt (ceded to Mainz in 1366) with Clausthal, Herzberg, and Herzberg Castle. The dominion also comprised the eastern exclave of Elbingerode, today part of Saxony-Anhalt.

Duke Wolfgang of Brunswick-Grubenhagen (1531–1595) was the Prince of Grubenhagen from 1567 to 1595.
Wolfgang was born on 6 April 1531 in Herzberg, the fifth son of Duke Philip I of Brunswick-Grubenhagen and his second wife, Catherine of Mansfeld. He succeeded his brother, Ernest as Duke in 1567, governing the tiny Principality of Grubenhagen. Like most of his predecessors, he had financial problems, so he was often forced to sell or pledge major parts of his possession and he had to demand high taxes.
In 1581 he gave the citizens of Herzberg the right to provide for their own fuel and timber as well as leaves for fertilizing their fields. He attempted to improve the educational level in his country by establishing a court school in Herzberg. In 1593 he dissolved the county of Lauterberg-Scharzfeld as a fief, to counter the demands of the Counts of Stolberg. In the same year, he confirmed the Harz mining regulations of 1554 and gave Herzberg citizens the right to brew beer and a licence to trade wine.
He created a pleasure garden for his wife Dorothea of Saxe-Lauenburg (born 11 March 1543; died 5 April 1586) below Herzberg Castle.
Wolfgang died on 14 May 1595 died in Herzberg) and was buried next to his parents, brothers and wife in the crypt of the St. Giles Church in Osterode am Harz.
He had no children. His younger brother Philip II inherited the principality. On Philip II's death, the Grubenhagen line of the House of Welf died out.
Philip II (2 May 1533 – 4 April 1596), Duke of Brunswick-Lüneburg, a member of the House of Welf, was the last ruler of the Principality of Grubenhagen from 1595 until his death. When he died in 1596, the Grubenhagen branch of the Welfs became extinct, whereafter the principality was occupied by Duke Henry Julius of Brunswick-Wolfenbüttel.

more on https://en.wikipedia.org/wiki/Principality_of_Grubenhagen , https://en.wikipedia.org/wiki/Wolfgang,_Duke_of_Brunswick-Grubenhagen , https://en.wikipedia.org/wiki/Philip_II,_Duke_of_Brunswick-Grubenhagen