Its magnitude was meant to reflect the power of this chivalrous order, admired throughout the medieval world. In 1226 the Teutonic Knights made contact with Conrad, Duke of Mazovia, who endowed them with the lands of Chełmno in return for their pledged promise of protection against attacks by the pagan Prussians.

Construction work on the castle began in 1274. In 1309 the castle, known as Mary’s Castle (Marienburg), became the capital of the Teutonic state, the Grand Master taking up residence there in 1324. The castle was built in stages on a post-glacial hill overlooking the River Nogat, eventually forming a Gothic complex of nearly 700 m in length. The High Castle (built in 1276-1280 and 1331-1344) is the monastic heart of the complex, raised in square layout with an internal courtyard flanked by cloisters, and surrounded by deep moats and a ring of defensive walls. It is here that we find the chapter house (with its intricate triradial umbrella vaults) and the Castle Chapel of St Anne (the crypt of the grand masters). The Church of the Blessed Virgin Mary (the Order’s main church), measuring 38 m long and 14.4 m high, was expanded in 1331-1344. The chancel, projecting beyond the face of the wall, now terminated in a triple apse featuring an 8-metre-high mosaic-encrusted bas-relief of the Order’s patron saint on its outer façade. The arcaded cloisters around the courtyard, the chapter house and in particular the chapels are furnished with lavish architectural and carved decoration (including figural bosses and elaborate portals). The bailey was extended, turning it into the spacious Middle Castle which served as the state’s administrative centre and provided accommodation for the most important of guests. The Grand Masters’ Palace, located at the end of one wing, is a masterpiece representing one of the most elegant seats of office in Europe, where defensive function gives way to opulence. The palace was raised in 1330-1340, and expanded from 1382 to 1399. Its rooms were heated by warm air conducted through a system of ducts connected to a furnace in the cellars. The Grand Masters’ Palace has two dining halls in the form of a Summer and a Winter Refectory. The latter is notable for its sublime fan vaulting supported by a slender granite pillar. The Grand Refectory is also noteworthy; measuring 15 × 30 m, and almost 10 m in height, it can accommodate up to 500 guests. In the 14th and first half of the 15th century the Lower Castle was extended to include an armoury (known as the karwan) and numerous ancillary buildings.

Malbork was regarded as an indomitable fortress (it was not until 1620 that it was conquered by the Swedes, though by that time it was merely a monument to military architecture). Ladislaus Jagiełło did not manage to enforce its capitulation in 1410, and when Casimir the Jagiellonian breached its wall he bribed a mercenary army to do so. For 300 years it served as a regional administrative office of the Republic and one of its best equipped arsenals. After the first partition of Poland the Prussian authorities converted the castle into barracks and storerooms, gradually destroying it.

In 1817 a programme of conservation work began, conducted by K. F. Schinkel and F. von Quast. The castle was painstakingly restored in 1882-1921 by K. Steinbrecht, only to be damaged again during the Soviet offensive of 1945 (the church chancel with its figure of Mary, the main tower and one wing of the Middle Castle being worst affected). Today the castle is an excellent illustration of changing perceptions in the significance of historic monuments and an example of the changes that have taken place in approaches to conservation in Europe. The work carried out here has played a hugely influential role in the development of research methods and conservation procedures used for European medieval architecture. The castle became a testing ground for interdisciplinary approaches to conservation practice, such as the use of probes to examine a building’s historic fabric, archaeological methods, and the compilation of drawn and photographic records. Many long-forgotten art and craft techniques were rediscovered at Malbork. The castle’s inclusion on UNESCO’s World Heritage List in 1997 underlined not only its position as an exceptional example of brick-built architecture, but also its value as a unique monument to conservation practices and policies.