Bohemia’s new government, formed of Protestant nobility and gentry, has given German military commander Ernst von Mansfeld the command over all of its forces.

Catholic nobles and priests have meanwhile started to flee the country.

Some of the monasteries as well as unfortified manors are evacuated and the Catholic refugees head for the city of Pilsen, where they think that a successful defense can be organized.

The city is well-prepared for a lengthy siege, but the defenses are undermanned and the defenders lack enough gunpowder for their artillery.

Mansfeld decides to capture the city before the Catholics are able to gain support from the outside.

This engagement, the first major battle of the Thirty Years' War, begins on September 19; the Protestant victory and subsequent capture of the city is to spark the Bohemian Revolt.

Mansfeld, after capturing Pilsen on November 21, demands one hundred and twenty thousand golden guldens as war reparations and an additional forty-seven thousand florins for sparing the city and not burning it to the ground.

The Holy Roman Empire, led militarily by Bavaria, soon gathers enough forces, however, and crosses the border with Bohemia, heading towards Pilsen and Prague.

Josef Groll brews the first pilsner beer in the city of Pilsen, Bohemia (now the Czech Republic). 

The city of Pilsen had begun brewing in 1295, but most Bohemian beers are top-fermented.

The taste and standards of quality often vary widely, and in 1838, consumers had dumped whole barrels to show their dissatisfaction.

The officials of Pilsen had founded a city-owned brewery in 1839, called Měšťanský pivovar Plzeň (German: Bürger-Brauerei, English: Citizens' Brewery – now Pilsner Urquell), which was to brew beer in the pioneering Bavarian style.

Brewers had begun aging beer made with cool fermenting yeasts in caves (lager, i.e., German: gelagert [stored]), which improved the beer's clarity and shelf-life.

Part of this research benefited from the knowledge already expounded on in a book (printed in German in 1794, in Czech in 1799), written by Czech brewer František Ondřej Poupě (Ger: Franz Andreas Paupie) (1753–1805) from Brno.

The Pilsen brewery recruited the Bavarian brewer Josef Groll (1813–1887) who, using new techniques and paler malts, presented his first batch of pale lager on October 5, 1842.

The combination of brighter malt prepared by English technology, Pilsen's remarkably soft water, local Saaz noble hops from nearby Žatec and Bavarian-style lagering produces a clear, golden beer that is regarded as a sensation.