[4] Granted the titles of Landpfleger[5] (per Sclavoniam et Prusiam preceptor) and Landmeister, Balk led the Teutonic Knights during the conquests of Culmerland, Pomesania, and northern Warmia in the first decade of the Prussian Crusade, the 1230s.

He utilized guerilla warfare, forest ambushes, and his white-cloaked cavalry in winter campaigns; the master crossed the Vistula in 1231 to hang a Prussian chief from a sacred oak tree.

[citation needed] Under Balk's leadership, castles were built at Marienwerder (Kwidzyn), Culm (Chełmno), Elbing (Elbląg), Thorn (Toruń), and Rheden.

The upset Livonian Brethren refused to cooperate with Balk, who traveled to Italy to seek aid from Grand Master Hermann von Salza and Pope Gregory IX.

Balk received little assistance, as Gregory IX was feuding with Emperor Frederick II and Hermann von Salza died in Salerno.