Nicolaus, the Catholic archdeacon of Durrës had been instructed to make preparations for the mission. Shortly after, however, Demetrio stopped the process because he didn't consider it important any longer. He had defeated Đorđe Nemanjić, a Venetian vassal whom he bordered to the north and thus felt less threatened by Venice. Nemanjić had previously promised military support to Venice if Progoni attacked Venetian territory, in a treaty signed on 3 July 1208. In 1208, he also had secured a marriage with Komnena Nemanjić, who was both the daughter of Stefan Nemanjić, rival of Đorđe Nemanjić and grand-daughter of the last Byzantine Emperor Alexios III Angelos. In this context, because of the relation of his consort to the Byzantine imperial family, Demetrius was recognized by the title of panhypersebastos. After the death of the Catholic archbishop of Durrës, the Venetians and Progoni - each in their respective territories - seized church property. For his actions against church property, he was excommunicated. He used the title princeps Arbanorum ("prince of the Albanians") to refer to himself and was recognized as such by foreign dignitaries. In the correspondence with Innocent III, the territory he claimed as princeps Arbanorum was the area between Shkodra, Prizren, Ohrid and Durrës (regionis montosae inter Scodram, Dyrrachium, Achridam et Prizrenam sitae). In general, Progoni brought the principality to its climax. The area the principality controlled, ranged from the Shkumbin river valley to the Drin river valley in the north and from the Adriatic sea to the Black Drin in the east. In Latin documents, Demetrius was is also referred to as iudex. In Byzantine records, he is titled as megas archon and after the consolidation of his rule as panhypersebastos. In 1209, in search for allies, he also signed a treaty with the Republic of Ragusa which allowed for free passage of Ragusan merchants in Albanian territory. The following year, an agreement was concluded between the Republic of Venice and Michael I Komnenos Doukas of the Despotate of Epiros under which Doukas would become a vassal of Venice, if the republic recognized his claims up to the Shkumbin river valley, a core area of Arbanon. In 1212, Venice also allowed for the possession of the coastal duchy of Durrës to pass to Michael and abandoned its direct control of central Albania. The agreement had dire consequences for the principality, which surrounded by hostile forces, seems to have been