At the end of the Bronze Age and in the Iron Age (1200 B.C.-800 A.D.) waves of violent migrations, wars, conquests swept over Europe and the Carpathian basin.

We know names for the various peoples that lived in the area, so from that time we can speak about concrete peoples, not only cultures. Equestrian Kimers, armoured Cotinus-Celts, nomadic Scythians, Jasig-Sarmatians, Gepids and Avars dwelt on this land in the time of the great migration. Archaeological remains show that the population lived in village settlements, and earthworks were built on the higher places in the Sajó valley. On the place where the stone-castle of Diósgyőr now stands (according to some researchers) there used to be a ring-formed fortification (győr) from the Iron Age. Other sources mention that German historians called the Avar settlements "gyűrű", which means "ring" in Hungarian. In this way, the name "győr" could come from the Avar-ring before the time of the Hungarian conquest.

In the 5TH century, one of the Scythian tribes coming from the East occupied the area called Borsod County today. The objects made of bronze (decorated mirrors and gold deer used as shield-ornaments) are typical of the Scythian metalwork. A gold deer was found in a princely grave in Mezőkeresztes-Zöldhalompuszta, in the neighbourhood of Miskolc. That piece of art, weighing 409 grams, may have belonged to a chief and decorated his shield. On the Northeastern side of Miskolc some parts of a typical urn-grave Scythian cemetery were excavated.

The next people in the area were the Celts, who lived together for a while with the Scythians before ousting them. They came from France and reached North-Hungary around 350 B.C. They lived in tribes and made their living by keeping animals and cultivating the land. The centre of the Cotinus tribe was built above Diósgyőr (on the Nagysánc-peak). They mined iron in the Bükk-mountains. The Nagysánc earthwork in Bükkszentlászló was probably an important fortification for them. The first find of 367 coins was discovered in 1846. This treasure was taken to Vienna, where it is in a private collection today.

During the first wave of migrations, Roman legions occupied the West part of Hungary. Germans, and from the East Sarmatians, arrived in the lands the Romans kept under control. The remains of the German-Kvad culture were excavated in the downtown of Miskolc (on the Erzsébet square and around Sötétkapu).

Relics of Avar culture from the second wave of migrations have also been uncovered. The Avars invaded the lands of present-day Hungary in the 7-8TH centuries. During the excavations of Avar cemeteries on the border of Miskolc, many pieces of jewellery made of bronze, copper, and iron tools and harnesses were dug out.