The castle of Klapý was founded on a high isolated hill in the Central Bohemian mountains during the second half of the 13th century by either the king or the lords of Lichtenburg.

In 1335, when it is first recorded, King John of Luxembourg sold it to Zbyněk Zajíc of Valdek, who changed its name to reflect the hares in his coat of arms (Hasenburg).

The castle has a bipartite layout; however the mutual chronological connection of both parts is not clear. The lower castle is dominated by a round Black Tower, while the upper castle has a polygonal White Tower, situated inside the oval created by the chemise walls, adjacent to which are three buildings. The biggest and oldest of these was on the southern side; a more recent outer bailey was evidently situated under the parkán (outer ward) wall on the western side.

The southern and northern buildings in the upper castle developed at the same time as the White tower was enhanced under Zbyněk Zajíc.

In the first third of the 15th century the fortified town of Podhradín, with a church, grew up under the castle; however it was soon destroyed.

During the Hussite wars Házmburk was used as a base by Sigismund of Luxembourg.

During the later part of the 16th century it was abandoned.

In the second half of the 19th century the Romantic ruin of the castle became a much sought after subject for painters.

The first work to stabilise it was launched at the end of the 19th century.