In the Book of Henrykowska - one hundred pages chronicle of the Cistercian abbey originating from 1270 - there is the oldest Polish sentence! It is located in the description (on page 24) of Brukalice villages belonging to the abbey. The written sentence was said (according to the chronicler) by a Czech knight to his Polish wife.

Author: Bonio under Creative Commons Uznanie autorstwa – Na tych samych warunkach 3.0

In the transcription, the first written Polish sentence sounds like this: "Daj ać ja pobruszę, a ty poczywaj", which simply means: "I'll do the work, and you (my wife) rest". The chronicller was so pleased by the man who cared about his wife  that he wanted to write his sentece to Chronicle.