Grevenburg castle was built in 1350 by Count Johann III of Sponheim-Starkenburg and replaced Castle Starkenburg as the residence of the Rear County of Sponheim. With the extinction of the ruling male line of the Rhenish branch of the House of Sponheim in 1437 the castle became seat of the bailiff of the new Counts to Sponheim.
In 1680 it was conquered by Louis XIV of France and was extended, together with the fort of Mont Royal in the horshoe bend of the Mosel north of the town of Traben-Trarbach as a part of the fortifications. During the War of the Spanish Succession (1701–1714), in 1702 it was taken by the French under Taillardin and in 1704 on the express orders of the commanding officer John Churchill, 1st Duke of Marlborough it was overpowered by Friedrich das Wehrschloss. The badly damaged castle was then occupied by the Dutch. In 1730 it was repaired by the Electorate of Trier for the defence of Koblenz and the Rhine river. In the War of the Polish Succession it was taken after three weeks' siege for the fourth and last time by the French who destroyed it in July 1734. The castle was blown up, huge chunks of it have plunged into the valley beneath.
Of the castle, although only the western wall of the former keep remains, the foundations are largely intact.
References:House of the Blackheads (Melngalvju nams) is a building situated in the old town of Riga. The original building was erected during the first third of the 14th century for the Brotherhood of Blackheads, a guild for unmarried German merchants in Riga. Major works were done in the years 1580 and 1886, adding most of the ornaments.
The structure was bombed to a ruin by the Germans June 28, 1941 and the remains demolished by the Soviets in 1948. The current reconstruction was erected from 1995 to 1999. Today the House of Blackheads serves as a museum and sometimes concert hall.