Complex sentence: The treaty, confirmed by magnates and nobles of both duchies, made both Mestwin and Przemysł II either a successor per donatio inter vivos or his successor in all his possessions, and Mestwin remained the Pomerelia ruler until his death in 1294.
Split into simpler sentences: The treaty, confirmed by magnates and nobles of both duchies, made both Mestwin and Przemysł II either a successor per donatio inter vivos or successor in all his possessions. It is known that Mestwin II remained the Pomerelia ruler until his death in 1294.