Whether the Slovaks already existed as a separate nation? How can you be sure?

There needs to be distinction made between nation and state.

Slovaks indeed never existed as separate state (except for during WWII) until 1993. Idea of Czechoslovakia only first came into being after Versailles Treaty (when Austro-Hungary fell apart).

However, Slovak nation as such, has existed always, just never had nation state of their own. First state created out of independent Slavic tribes which included Slovaks was Moravian Empire, then came Hungarian Empire, then came Hapsburg Empire, then came Austro-Hungarian Empire, then came Czechoslovakia and then only much later did Slovaks have own state.

One can question theory that Slovaks and Slovenes were once one and same people divided by Huns, that is possible. I think fact that their name is very similar, their flags, their folk costumes, their cuisine, their architecture etc. is no coincidence, so I personally believe it, but no doubt that Slovaks have existed as folk since ancient times:


So, when Hungarians say that Slovakia is artificial nation, maybe they only have right to extent that they have never had own state before (unlike Hungarians, who have had state since 1000 AD), but they cannot deny existence of their folk as nation.