Celje's development in the early Middle Ages was extremely slow. Compared to other Slovenian towns, it was granted its market or town privileges rather late. Despite the preservation of the name Celje and the fact that the mediaeval town was built on the ruins of the Ancient Celeia, there was in fact no continuity in the development of the town from the Antiquity into the Middle Ages, although its name is often mentioned in this transitory period.
For example, a document from 824, a gift deed between Emperor Louis I the Pious and the Church of Aquileia, mentions 20 tenant farmers from Celje (in loco que dicitur Zellia). This is followed by a period until the first half of the 12th century in which there is no information about the existence of Celje. A document from 1137 mentions a borderer (resident) of Celje (Guntherus marchio de Cylie); a few decades later, this is followed by reference to: Pernhardus de Cilie as witness (1185); minister of Celje Rubpertus plebanus de Cilie (1229); and again as witness to the Count of Heunburg (Vovberk), knight Hiltbrando de Cili (1241). It is quite clear that before 1323 when Celje is first mentioned as a mediaeval market, the settlement was the seat of the margraviate Saunia, where a manorial system must have been in place, with numerous craftsmen who also produced for the market. Taking into account the likely, although sadly still not proven, notion that the first Minorite convent was established in Celje in 1241, knowing that Minorites only inhabited towns and major markets, we can confirm the thesis that Celje had the character of an important urban settlement, e.g. a major market, in the 13th century. The notable role of the Celje of that period is also attested to by the references to numerous Celje nobles, and especially the reference to Celje in Parzival, the German romance about knightly adventures, by Wolfram von Eschenbach, known throughout Europe and written far from our lands.