Kost Castle

Kost stands not on a hilltop but on a rock spur where three watered valleys meet, ringed by ponds whose dams could be breached to flood the approaches. The donjon is the Bílá věž, and the tower of trapezoidal plan has its corners set towards the likeliest lines of catapult fire to make shot glance off.

Archaeology in 2019–2020 dated the foundation to the first half of the fourteenth century, the work of Beneš III of Vartenberk, who in 1349 first wrote himself Beneš of Kost and by the late 1350s said he lived there. He died in 1358; his sons Petr and Markvart held the castle undivided until at least 1371 and divided in 1373, Petr keeping Kost. Petr, a considerable courtier of Wenceslas IV, then had the first castle almost entirely pulled down and rebuilt, read as matching his standing. He died in the second half of 1402.

Kost passed by marriage to Jan of Kunštát and Poděbrady, and in 1414 to Mikuláš Zajíc of Hazmburk, first named lord on 12 March that year. Through the Hussite wars his Kost was a mainstay of the Catholic side, and priests driven from their parishes sheltered there, among them Ondřej Hrnčíř of Rokycany, who copied out Bibles in the Red Tower. Folk tradition has Jan Žižka besieging the castle and leaving with 'the rock belongs to the devil and the bone to the dog'; Rudolf Anděl assigned the words instead to a royal captain at the later Poděbrady-war sieges.

Mikuláš's sons Jan and Oldřich, who shared Kost after 1459, had helped elect George of Poděbrady king and later joined the opposing Zelená Hora union; the royal army besieged the castle in 1467 and again in 1469, and each time Jan Zajíc averted its capture by concluding a truce with the king. The brothers stayed in the service of Matthias Corvinus of Hungary, and only at the diet in Prague in 1479 did Jan swear loyalty to King Vladislav.

Jan Zajíc died in 1495 and both his sons within two years; in 1497 the minor heir's guardian sold Kost and Trosky to Jan of Šelmberk to clear the debts of the earlier wars, and Jindřich of Šelmberk sold both on to Jan of Biberštejn. Kryštof Popel of Lobkovic later gathered the shares and set a brewery in the outer bailey in 1576. Polyxena of Lobkovic bought Kost in 1622 and sold it in 1632 to Albrecht of Valdštejn, who paid only ten thousand of the 150,000 agreed, so after his death in 1634 she claimed the estate back; her son sold it on 7 October 1637 to Count Heřman Černín of Chudenice.

Imperial troops under Count Colloredo occupied the castle in 1635, and on the night of 18–19 May fire burned almost the whole palace wing of the core. In the spring of 1640 eighteen regiments under Ottavio Piccolomini camped by Sobotka, and the captain had to pay and feed a garrison of twenty-five men, and feed six Swedish prisoners. Demolition was proposed in 1658, the military engineer Pieroni having reported that Kost might serve the emperor's enemies as a fortress; Sylvie Kateřina Černínová of Millesimo appealed that no army had used it so in the recent wars and that much of its walling was already down, and through delays the matter was forgotten.

Kost had gone a century without serving as a lordly seat when Humprecht Jan Černín acquired it. In 1689 the vaults of the courtyard galleries gave way; in 1690 the medieval walls of the Vartenberk palace collapsed and the three remaining palaces were turned over to storing grain. Debt carried it out of Černín hands in 1738, to Václav Kazimír Netolický of Eisenberk, and thence to the Vratislavs of Mitrovice.

The last fighting came in the Austro-Prussian war of 1866, when men of the Cheb regiment held the castle. On the evening of 28 June they ran into Prussian patrols and the exchanges went on into the next day; the Austrians pulled back inside the walls, beat off two assaults, then withdrew to the army massing at Jičín, and the Prussians took the castle. The Vratislav male line ended in 1867, and after a suit among the heiresses Kost was awarded in 1872 to their kinsman Flaminio dal Borgo.

Conservation work followed in 1874–1875. The state took the castle in 1945; fire on 27 September 1946 cost the Biberštejn palace its roof, and restoration began under Břetislav Štorm after an architectural survey in 1953. Giovanni Kinský dal Borgo recovered it by restitution in 1992 as his mother's heir. Protected as a cultural monument, it draws over seventy thousand visitors a year, and the works finished in 2021 — drainage, wall and rock stabilisation, rampart repairs — cost over 100 million crowns.