The history of the castle leads us back to the beginning of the 12TH century. It became a possession of the king in 1128. After a couple of decades Ernye Bán took hold of it. It was his son's, István palatine's achievement that it was transformed into a splendid palace, both outside and inside.

Beginning in 1340, the castle became a possession of the queens. The income of the lands belonging to the castle could cover the prevailing queens' expenses.

Louis I, the great king of Hungary, liked to spend his time in the castle too. One of the reasons for it certainly was the nearby main route leading to Poland. From that place he could keep contact with the other parts of his country. After Louis had been crowned the king of Poland as well, Diósgyőr became the place of a rich royal household with hunting expeditions and parties (1370s). Not only did the Bükk-mountains provide a wonderful opportunity for hunting but also the king had a fishpond and a game preserve formed in 1355 too. As documents prove, the king, between 1363-1382, often spent his time in the palace, built and furnished with dazzling pomp.

After the death of King Louis I, King Sigismund (1387-1437) gave the castle to his wife, Barbara Cillei, as an engagement present. King Albert Hapsburg (1437-1439) gave it to Queen Elisabeth, King Matthias (1458-1490) to Catherine Podebrad, his first wife, then to Beatrix of Aragon the second wife. King Ulászló II also bestowed the castle upon his wife, Ann. Mary of Hapsburg, the wife of Louis II (1516-1526), was the last queen who lived amongst the walls of the Castle of Diósgyőr. From 1526 the royal owner did not stay in the castle; in fact, he did not even visit it.

The medieval Miskolc and the area between the Highland and the Lowland belonging to the Castle of Diósgyőr played only regional roles. It became a flourishing market town with two gothic churches, schools, mills on the Szinva stream, a broad street called Market (Piac), stone-houses and workshops of different crafts. Religious orders did not move into the town; nevertheless, many monasteries stood near by in the Middle Ages, e.g., two cloisters in the Bükk-mountains and close to the Castle of Diósgyőr, and a Benedictine one in Tapolca, which was established around the Hungarian conquest.

In the 15TH century, agricultural and wine-production slowly transformed Miskolc into a town which could rely more and more on craftmanship. At first the butchers formed a guild in 1508, followed by the shoemakers (1521) and the tailors (1531). The millers could not get permits for founding their guild, because they did not own their mills. Nevertheless, the mills on the Sajó River, the Szinva and the Hejő streams were a significant branch of industry.

Industry and agriculture separated step by step, and the increased weight of industry can be illustrated with the fact that most of the members of the town council came from amongst craftsmen in the 15TH century.

By the beginning of the 16th century, Miskolc had more than thirty charters of different privileges.
The town, now flourishing by the end of the Middle Ages, got into a more difficult situation starting in the middle of the 16TH century, when it was devastated by the Turkish sultan, the Hapsburg emperor, and the Prince of Transylvania just as much as by epidemics, fires, and floods.