In much of the European Union, a battle has been waged for more than a century between two breweries: Anheuser-Busch InBev (AB InBev), and the much smaller Czech-owned Budweiser Budejovicky Budvar. It’s one of history’s longest-running commercial disputes, and the subject of hundreds of legal cases this century.

The battle, of course, is over the name Budweiser.

It started in St. Louis, Mo., where enterprising German immigrants built a family brewery. Eberhard Anheuser, who had been a part-owner in a St. Louis-based brewery, bought out its investors in 1860, and renamed it E. Anheuser & Company. After marrying into the Anheuser family, Adolphus Busch would join his father-in-law’s business and become a part-owner. Anheuser-Busch was eventually acquired by Belgium-based global brewing company InBev in 2008.

Anheuser-Busch InBev (AB InBev) owns many well-known beer brands in the U.S., and its Budweiser brand remains a best-selling beer in the States as well as worldwide.

However, most Americans may be surprised to learn that AB InBev’s successful American lager can’t be found in Europe, where the parent company is based — at least not under the same name. This is because the Czech brewery Budvar, established in 1895, retains the right to use the Budweiser name.

Achieving this right wasn’t easy, however. Instead, a complex history lies behind the name “Budweiser,” and depending on where in the world you’re drinking it, the beer’s name may be different.

Although AB InBev claims to have brewed Budweiser beer since 1876, nearly 20 years before Budvar’s founding, Adolphus Busch’s decision to name the American lager “Budweiser” proves controversial. Translated to “of Budweis,” the name refers explicitly to a city in the Czech Republic, České Budějovice (Budweis in German or English), known for its breweries, one of which is Budvar.

When Budweiser Budvar took Anheuser-Busch to court in New York in 1896, according to a 2014 article in Time magazine, Adolphus Busch’s own statements in the New York district court were used against him: “The Budweiser beer is brewed according to the Budweiser Bohemian process,” Busch said in court. “The idea was simply to brew a beer similar in quality, color, flavor and taste to the beer then made at Budweis, or in Bohemia.”

These words only helped Budweiser Budvar to bolster its claims against AB InBev. A resulting court decision divided the two Budweisers into spheres of influence: Anheuser-Busch would use the name “Anheuser-Busch Bud” for its branding in much of Europe. Yet, as Benjamin Cunningham writes in his 2014 article, “the reverse is true in much of the rest of the world.” In the U.S. and Canada, meanwhile, Budvar is sold under the name “Czechvar.”

Things are even more complicated for Anheuser-Busch in Germany, where Bitburger, a local brewery and Germany’s top-selling draft beer brand, argued in court that the word “Bud” was too similar to its own trademark, “Bit.” Anheuser-Busch ultimately won that case in 2007.

In Italy, in 2013, the Italian Supreme Court also found itself settling a case over Budweiser. It ruled in favor of Budvar, agreeing that AB InBev could not use the name Budweiser in that country due to the Czech brewer’s existing brand. Italians, too, would have to drink “Bud.”

That same year, a U.K. court decision diplomatically decided that both AB InBev and Budvar had the rights to the name Budweiser, believing that consumers were savvy enough to tell the difference. This, too, is debatable, but proves even the “King of Beers” has its empirical limits. The Budweiser turf war rages on today.