In a tithe register of the Hersfeld monastery created between 881 and 899, Querfurt is mentioned for the first time as a place where Curnfurt im Friesenfeld is subject to tithing and was first titled castellum in a document from Emperor Otto II from 979. The castle there has been the ancestral home of the noble lords of Querfurt since the 10th century. Traces of the oldest surviving building structure also date from the 10th century, which are parts of the inner curtain wall and the granary and armory. The stone buildings were limited to the area between today's granary, the Dicker Heinrich keep and the castle church. These period solid buildings also underline the importance of the Querfurt noblemen. In 1004, at the same time as the foundation of a castle chapel, a canons' monastery was founded, which was followed from 1162 by the construction of a Romanesque church in the middle of the castle courtyard. In the 14th century, a burial chapel with the tumba of Gebhard XIV of Querfurt was added. The Fat Henry was built at the beginning of the 12th century, followed by the construction of the Martial Tower at the beginning of the 13th century and the construction of the Paris Tower at the beginning of the 14th century. The outer curtain wall was added around 1350. During the 15th century, mainly fortificational changes were made. The bastions and the west gate date from the period between 1460 and 1490. After the death of the last lord of the castle, Bruno IX. von Querfurt In 1496, Querfurt and its castle were confiscated as a fief of the Archdiocese of Magdeburg. Albrecht of Brandenburg then had structural changes made to the complex in 1528 and 1535. Towards the end of the Thirty Years' War, from 1640 to 1642, the fortress, which was considered impregnable, changed hands several times after heavy sieges and shelling. The subsequent period of occupation by the Swedes lasted from 1642 to 1650. In 1663, the imperial princes of Saxony-Querfurt made the complex their residence and thus Querfurt the capital of their territory. The so-called Princely House was therefore built between 1660 and 1668. Around 1700, new gun emplacements were built on the widened berm above the Zwinger, before Querfurt was built after the death of Adolph III. of Saxony-Weißenfels fell back to the Electorate of Saxony.
Source: Wikipedia