Burg Königsberg, Medieval fortress in Hesse, Germany.

Burg Königsberg is a castle site on a hilltop above the Königsberg district of Biebertal. The present two-storey villa-like house, built from 1924 on old retaining walls and cellar vaults, has a high slate hipped roof and a corner turret with a Welsh dome. Surviving medieval remains include the roughly ten-metre Altemarksturm, foundation traces of the palas, and circular zwinger and ring walls about 800 metres long.

Burg Königsberg was probably built around 1240/50 by Count Marquard von Solms, whose son Reimbold I called himself Count of Cunigesberg from 1257. In 1350 Philipp von Solms-Königsberg sold the castle and lordship to Landgrave Henry II of Hesse for 2,000 guilders; the line died out with him in 1363. In June 1647, during the Hesse War, Lower Hessian troops under Mortaigne de Potelles bombarded and burned the castle after a 48-man garrison surrendered. Rebuilt by 1654/56 as an administrative seat, the buildings were demolished in 1872–74; a villa-like house was built on the old walls from 1924.

The name Königsberg comes from Count Reimbold I of Solms, who called himself Graf von Cunigesberg from 1257 after his residence here. The writer Philipp Balthasar Sinold, known as Schütz, was born at the castle in 1657, son of the local Amtmann. After 1821 an Oberförsterei occupied the site, and around that time a tavern is said to have operated in the buildings.

A visit lets you explore the layout and sections of a medieval fortress with different functional areas. Expect uneven ground and steep pathways since the castle sits on elevated terrain with historical structures throughout.

The 10-metre Altemarksturm is the only surviving defensive tower; the ring wall and circular Zwingermauern still enclose roughly 800 metres of perimeter. The writer Philipp Balthasar Sinold, called Schütz, was born at the castle in 1657, son of the then Amtmann.