At the imperial Diet of Frankfurt, King Otto IV is officially recognized as the sole monarch; the king punishes the culprits involved in the assassination of his rival, the late King Philip of Swabia, including Henry IV of Andechs, the margrave of Istria (notices from the contemporary narrative source Cronica Sancti Petri Erfordensis moderna).
King Otto IV confirms the Duchy of Bavaria to Duke Ludwig of Bavaria and his heirs, bestows upon the same duke the farm of Mering with income of 200 marks, and the imperial fiefs of the murderers of Philip of Swabia - Count Palatine of Bavaria Otto VIII of Wittelsbach and Henry IV of Andechs, the margrave of Istria - including the Margraviate of Istria.
King Otto IV holds an imperial diet in Augsburg where he deals, among many other things, with the fate of the condemned murderers of King Philip and the Margraviate of Istria (notices from contemporary narrative accounts, Otto of St. Blasien’s and Conrad of Scheyern’s chronicles).
Otto IV, King of the Romans, confirms the rights of the Patriarchate of Aquileia over the Duchy of Friuli, including the incomes from the administration of criminal justice, and all documented agreements made between Patriarch Peregrine I and Count Maynard I of Gorizia as well as Patriarch Ulrich II and Count Engelbert II of Gorizia regarding advocacy and other matters.
Otto announces to all the subjects of the Empire in Italy that he has appointed Patriarch Wolfger of Aquileia imperial legate for Lombardy, Tuscia, the Duchy of Spoleto and the Marches of Ancona and Romaniola, commanding them to receive him honorably and to recognize his decisions in imperial affairs.
King Otto IV invests Patriarch Wolfger with imperial regalian rights and attests that his successors do not need to journey to German lands to receive the regalian investiture because the patriarchs of Aquileia are one of the Italian ecclesiastical princes.
On the behest of Wolfger, the patriarch of Aquileia, and other princes gathered at the Diet of Augsburg, King Otto IV accepts the resignation of the Margraviate of Istria from Duke Ludwig of Bavaria and donates the same Margraviate to Patriarch Wolfger and the Church of Aquileia.
Otto IV, Emperor of the Holy Roman Empire, confirms the donation of the Margraviate of Istria to the Patriarchate of Aquileia.