Editing Sixth Crusade (section)

=== Situation in Italy ===
After agreeing with Honorius to launch a Crusade before 1228, Frederick summoned an imperial Diet at [[Cremona]], the main pro-imperial city in [[Lombardy]]. The main arguments for holding the Diet would be to continue the struggle against heresy, to organize the crusade, and to restore the imperial power in northern Italy, long usurped by the numerous communes located there. Those assembled responded with the reformation of the [[Lombard League]], which had already defeated the emperor [[Frederick Barbarossa|Frederick I]] in the 12th century, and again Milan was chosen as the league's leader. The Diet was cancelled as well as the [[Peace of Constance|Truce of Constance]]. The situation was stabilized only through a compromise reached by Honorius between Frederick and the league. During his sojourn in northern Italy, Frederick also invested the Teutonic Knights with the territories in what would become East Prussia, starting what was later called the [[Northern Crusade]]s.<ref name=":23">Arthur William Holland (1911). "[[wikisource:1911 Encyclopædia Britannica/Frederick II., Roman Emperor|Frederick II, Roman Emperor]]". In Chisholm, Hugh (ed.). ''Encyclopædia Britannica''. '''11.''' (11th ed.), Cambridge University Press. pp. 46–49.</ref>