At the extreme risk of being reductive… it really didn’t.

Slavic identity and Czech nationalism were movements which were driven by the retreating institutional authority of first the Holy Roman Empire and then the Austro-Hungarian Empire. But for centuries, cities such as Prague, Carlsbad, and Hradec Kralove would not have been what we would now view as “Czech” cities. It was not until the 19th century that Slavic nationalism became a powerful political force, and this was driven largely by populist movements not centered around the major cities or universities - with the notable exception perhaps of Charles university, which is one of the main drivers for the revitalization of the Czech academic tradition and the formalization of the Czech language as an academic language. Even so, the result was a blending of traditional Czech with Latin forms of grammar and German vernacular which remain a part of the living language today. Nothing in Slavic culture remained untouched by this influence.

Now, it is true that pockets of Slavic culture survive remarkably intact for centuries even when Czechs had no formal political organization. But in part this stands to reason: as an ethnic and linguistic minority, Czechs bound together in an archipelago of settlements that stretched from the sudenland all the way to Romania, and maintained intermarriage and interchange of culture between these groups and adjacent cultures such as the Rusinian, Sorbían, and Morav cultures. It was not until later in the 19th century that Czech again gained prominence once again in major cities.

The Czech culture was revived partly by the process of Czech industrialization. As worker wealth and the artisan class grew, there was a larger receptive and literate audience looking for entertainment, music and literature in the traditional language. As in so many other stories, the change came when workers began to have money to spend, and could “vote with their crowns” so to speak, and chose to support cultural traditions that reflected their heritage and identity. By the dawn of WW2, this political base of educated working and middle class people had become the ascendant political center of the country, right as nationalism bloomed all over Europe for much the same reasons. The postwar settlement and expulsion of German minorities only enhanced that trend.

What’s also interesting is that your question is also somewhat correct in guessing “mountains.” Indeed, Bohemian geography favors isolated hills and valleys that maintain low and steady populations over many centuries. The Czech lands are the risen floors of ancient seabeds surrounded by an ancient reef of basalt rock, making for craggy jagged hills that encircle Bohemia and make it hard to invade except across the central axis (not coincidentally why the Germans used it). In fact the western hills of Bohemia are called “Czech Switzerland” to this day.

This created the conditions first for a great deal of localized political stability (as it’s hard to have wars in hill country) and for small pockets of the old culture to continue to thrive for centuries.

Still not all of these linguistic or cultural traditions did survive. Try and find a Sorbian speaker today. All that really remains of that culture are the place names, and recently a small revival of the language. Hundreds and thousands of villages today bear names that even the local people don’t know the meaning of, because they are so old.

It’s not a history text per say, but I found Madeleine Albricht(ova)‘s Prague Winter insightful on the nature of the Czech national tradition from a somewhat unique perspective.

Someone here can surely recommend a better source than I can on European nationalism. It’s a topic that interests me, but that I’m not as well versed as I’d like to be. I just happen to know more about the Czech national identity since I live here and have studied it myself for decades.