I plead ignorance of medievil history. Please explain the connection between Celtics, who I understand to be the various Brit peoples; English, Irish, Scottish.....and Slovaks, which I would take to be Czechs, Polish and other related Eastern Europeans. Thank you.
Celtic tribes conquered parts of Slovakia towards the end of the Iron Age. These coins are from then.
The medieval era came after the fall of the Western Roman Empire beginning in the 5th century AD. So these coins are about a thousand years before the start of the dark ages in Europe.
The Celts came from the east, Central Asia probably; the various Germanic people came in later, pushing them out and/or absorbing them; Slavic peoples came in during the so-called Dark Ages, probably from Central Asia.