Frederick II, Holy Roman Emperor led the Sixth Crusade to the Holy Land in 1228, and claimed the kingship of Jerusalem by right of his wife, Queen Yolande of Jerusalem, who had inherited the title of 'Queen of Jerusalem' from her mother, Maria of Montferrat, the wife of John of Brienne.
Frederick II, Kaisar Romawi Suci memimpin Perang Salib Keenam ke Tanah Suci pada 1228, dan mengklaim jabatan raja Yerusalem atas hak istrinya, Ratu Yolande dari Yerusalem, yang mewarisi gelar 'Ratu Yerusalem' dari ibunya, Maria dari Montferrat, istri dari Yohanes dari Brienne.