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:
Derbent is the southernmost city in Russia, occupying the narrow gateway between the Caspian Sea and the Caucasus Mountains connecting the Eurasian steppes to the north and the Iranian Plateau to the south. Derbent claims to be the oldest city in Russia with historical documentation dating to the 8th century BCE. Due to its strategic location, over the course of history, the city changed ownership many times, particularly among the Persian, Arab, Mongol, Timurid, Shirvan and Iranian kingdoms.
Derbent has archaeological structures over 5,000 years old. As a result of this geographic peculiarity, the city developed between two walls, stretching from the mountains to the sea. These fortifications were continuously employed for a millennium and a half, longer than any other extant fortress in the world.
A traditionally and historically Iranian city, the first intensive settlement in the Derbent area dates from the 8th century BC. The site was intermittently controlled by the Persian monarchs, starting from the 6th century BC. Until the 4th century AD, it was part of Caucasian Albania which was a satrap of the Achaemenid Persian Empire. In the 5th century Derbent functioned as a border fortress and the seat of Sassanid Persians. Because of its strategic position on the northern branch of the Silk Route, the fortress was contested by the Khazars in the course of the Khazar-Arab Wars. In 654, Derbent was captured by the Arabs.
The Sassanid fortress does not exist any more, as the famous Derbent fortress as it stands today was built from the 12th century onward. Derbent became a strong military outpost and harbour of the Sassanid empire. During the 5th and 6th centuries, Derbent also became an important center for spreading the Christian faith in the Caucasus.
The site continued to be of great strategic importance until the 19th century. Today the fortifications consist of two parallel defence walls and Naryn-Kala Citadel. The walls are 3.6km long, stretching from the sea up to the mountains. They were built from stone and had 73 defence towers. 9 out of the 14 original gates remain.
In Naryn-Kala Citadel most of the old buildings, including a palace and a church, are now in ruins. It also holds baths and one of the oldest mosques in the former USSR.
In 2003, UNESCO included the old part of Derbent with traditional buildings in the World Heritage List.