If the pen is mightier than the sword, that sword which is also a pen thus holds infinite might

As diligent as she was, it took the newest alicorn very little time to assess that the ancient prophecy had been rather sloppily translated. While the sword in the book could indeed only be removed by a certain chosen individual, the original word of the prophecy did not specifically refer to a “Librarian King” as much as a more generalized “librarian Ruler.”
With nothing to lose by trying, and everything to gain by finally finding a way to unseal both the sword of legend and the infinite book of infinite knowledge it held shut, the princess took a chance and pulled…

Ten legendary weapons 1/10: Lexicalibur (and the Omnicon, infinite book of infinite knowledge)