Or in English, Happy Jan Sobieski Day. On today's date in 1683, the Polish king Jan Sobieski, having led an army of Poles, Germans and Austrians to the vicinity of Vienna the day before (9/11), attacked and defeated the Turks, who had been besieging the city for about two months. Some of the Turks retreated rather hastily, leaving behind supplies of hard brown beans from which they brewed a hot beverage. Thus, central Europe was allowed to remain Christian instead of becoming Islamic, and western civilization started to drink coffee.
Czytaj więcej, I mean, read more at Badass Of The Week (NSFW language), Encyclopædia Britannica, New Advent, HistoryNet and Utica Phoenix.
Linguistic note: Polish and most other Slavic languages are case-inflected, similarly to Latin and Greek. Thus, the form of a noun and any adjective(s) modifying it changes to indicate the noun's grammatical function. The genitive case is mainly used to convey the notion "of". In this way, the idea of "of Jan Sobieski" is rendered "Jana Sobieskiego". The genitive has other functions, including greetings and wishes. Thus, "wesoły dzień" ("happy day") becomes "wesołego dnia" (literally "of a happy day"). The result of all this is that all four words of this post's title are in the genitive.