Vimberk, also known as Melmatěj, is a vanished castle situated on a river terrace above the Klábová River valley near Strašice in the Plzeňský kraj region of the Czech Republic. Constructed in the late 13th century, it served as a strategic fortification likely overseeing nearby iron ore mines. Despite its historical significance, no written records of Vimberk exist; its history is pieced together through archaeological findings.

The origins of Vimberk trace back to the late 13th century when an unnamed ruler built it during a period marked by increased fortification efforts across Europe. This era saw Bohemia under the Přemyslid dynasty, transitioning towards a more centralized monarchy. The castle's strategic location suggests its role in overseeing and protecting nearby iron ore mines, reflecting the economic activities of the time.

Architecturally, Vimberk is characterized by an archaic and transitional design typical of early medieval fortifications. The primary construction material was wood, as evidenced by the lack of surviving stone or mortar remnants. Defensive features included a moat and ramparts, with the main entrance likely located in a northern breach. A notable feature is an object carved into the rock on the western side, possibly serving as a granary.

Ownership of Vimberk changed hands over time. Initially built by an unnamed ruler, Nachval z Osvračína held it as a pledge holder in the 14th century. In 1325, Petr I. z Rožmberka acquired it from Nachval and integrated it into his domain. The castle's fortunes were closely tied to these influential figures.

Key events at Vimberk include its destruction by fire around mid-14th century during a conflict involving King Charles IV of Bohemia. In the early 1350s, amidst a conflict between South Bohemian and German nobility, King Charles IV seized the opportunity to attack the Rožmberk family. In February 1352, royal forces captured the Rožmberk castles Strašice and Chlukov, leading to Vimberk's destruction.

Today, the ruins of Vimberk are accessible via a blue-marked tourist trail from Dobřív to Strašice. The site offers scenic views of the Klábová River and is surrounded by natural landscapes. Despite its vanished state, the remnants of Vimberk provide valuable insights into medieval fortification practices and regional history.

Vimberk stands as a testament to the strategic importance of castles in medieval Europe and their role in economic activities such as mining. Its ruins invite visitors to explore a piece of Bohemian heritage, offering both historical intrigue and natural beauty.