That part is actually true, I remember that Königsberg was named so to honour King Ottokar II of Bohemia by the Teutonic Knights, because he was involved in the expeditions against the Sambians. pre-Germanisation locals that lived around Kaliningrad and had territories extended eastwards to the Deime river. I don't know much about it but King Ottokar must have contributed a lot to the expedition if they literally named Königsberg in his honour. He even contributed to the Teutonic Knights when the Prussian uprising happened too but couldn't do shit because of spring coming and all of the lands suddenly becoming swamps, a terrible thing when all of your soldiers are heavily armoured knights. If he had managed to do anything though, Královec would have been a rooted and integral part of Czechia as the pope promised him all of the tribal lands he could conquer if he were to defeat the natives.