Original sentence: A son named Casimir was to have been married to the daughter of emperor Frederick III but he instead chose a religious life, eventually becoming canonized as St.Casimir, in alliance with the Prussian Confederation, defeated the Teutonic Order, which in the ensuing Second Treaty of Thorn recognised Polish sovereignty over western Prussia and the Polish crown's overlordship over eastern Prussia.His marriage to Elisabeth of Austria, a member of the Habsburg house, eventually allowed his son Ladislaus to combine the thrones of Hungary and Bohemia.Neither was recognized by the empire, which continued as administrators of Prussia, nor by the pope.That same year, Casimir was approached by the Prussians for aid against the ruling Teutonic Order, which he promised; however, when he tried to annex Prussia, civil war broke out among Prussian cities, resulting in the  Thirteen Years War (1454-1466).The marriage also strengthened the ties between the houses of Jagiello and Habsburg
Edited sentence: A son named Casimir was to have been married to the daughter of emperor Frederick III but he chose to became St.Casimir, in alliance with the Prussian Confederation, defeated the Teutonic Order, which in the ensuing Second Treaty of Thorn recognised "Polish sovereignty" over western Prussia and the "Polish crown's overlordship" over eastern Prussia.Elisabeth was the granddaughter of Sigismund, Holy Roman Emperor and her marriage in 1454 put the House of Jagiello and their ongoing Habsburg marriages on close family relationship to the imperial rulers.His marriage to Elisabeth, Habsburg (Elisabeth of Austria) allowed his son Ladislaus to combine the thrones of Hungary and Bohemia.In the same year of his imperial alliance, Casimir was approached by the Prussians for aid, which he promised, but when he tried to annex Prussia, several years of civil wars (1454-1466) broke out between Prussian cities Thirteen Years War.Neither did any city, town or village in Prussia "become Polish" or change their official language to Polish or "belong to Poland", as it is erroneously claimed since the 20th century, nor did a "Polish ruler" ever become king of Prussia or any part thereof.Neither was recognized by the empire, who continued as administrators of Prussia, nor by the pope.The matter was still unresolved when the Reformation changed the situation completely