第6回十字軍
The Italians probably became aware of the Frisian Potestaat, in Dutch "op poten staan" in English 'on legs standing', like for instance king Henry on his painting (Dutch: "potestaat", German: "Potestat", English: "potestate") during the Sixth Crusade in 1228. According to privileges that were falsely ascribed to the Carolingian era, the "potestate" was chosen by council and he must be able to slay knights. Apocryphal historical writings mention the potestate as early as the Viking Age.