The first mention of the fort of Opoczen (oppidum Opoczen), standing on the site of the current castle, is in Kosm's Chronicle and dates back to the year 1068. The origin of the fort probably dates back to the time before the establishment of the early Czech feudal state and it can be assumed that it was one of the supporting points Principality of Slavník. The significant entry of Opočna into history occurs only in the first half of the 14th century with the founding of a Gothic castle and a small town. In the Hussite era, Jan Městecky of Opočn, at first a supporter of Hus's teaching, later an enemy of the Hussites, resided in the Opočen castle. In 1425, the Gothic castle was captured and destroyed by orphans, and the city suffered greatly due to the presence of the Hussites. Due to the intensive construction activity of the late Gothic period, the castle was restored, which in the course of the 15th century was replaced by several owners in addition to the Valečovský from Hrádek and Valečov. From this time, a massive round tower called the Hládomorna and the remains of the fortifications have been preserved. At the end of the 15th century, Opočno was acquired by the important Czech noble family Trčký z Lípa.