Wow. Ok yeah. I just found and laboriously transcribed two pages from Jan Dlugosz for his entry on 1466, which are mostly about the siege of Chojnice but mention Bytow twice. This god damn website decided to log me out in the middle of transcribing all that so when I posted it, it disappeared. Wow. I an see that Titivillus is still out to destroy me after all these years.
The short version is that according to Jan Dlugosz, Bytow was occupied by Silesians in the service of a local duke loyal to the Teutonic Order, until shortly after the fall of Chojnice to the Poles, after which it was purchased by the Polish King for the sum of 8,000 florins, and went into Polish hands.
This was two months before the end of the 13 Years War between the Teutonic Knights vs. the King of Poland and the Prussian cities (Prussian Confederation).
Once my morale levels have recovered I may try again to transcribe the passage, as it has pretty interesting details about the siege of Chojnice.