part because of the increasing pressure from threats during the Barbarian Invasions. From the 6th century into the 7th century, the Slavs crossed the Danube and largely absorbed the indigenous Ancient Greeks, Illyrians and Thracians in the Balkans; thus, the Illyrians were mentioned for the last time in historical records in the 7th century. In the 11th century, the Great Schism formalised the break of communion between the Eastern Orthodox and Western Catholic Church that is reflected in Albania through the emergence of a Catholic north and Orthodox south. The Albanian people inhabited the west of Lake Ochrida and the upper valley of River Shkumbin and established the Principality of Arbanon in 1190 under the leadership of Progon of Kruja. The realm was succeeded by his sons Gjin and Dhimitri. Upon the death of Dhimiter, the territory came under the rule of the Albanian-Greek Gregory Kamonas and subsequently under the Golem of Kruja. In the 13th century, the principality was dissolved. Arbanon is considered to be the first sketch of an Albanian state, that retained a semi-autonomous status as the western extremity of the Byzantine Empire, under the Byzantine Doukai of Epirus or Laskarids of Nicaea. Towards the end of the 12th and beginning of the 13th centuries, Serbs and Venetians started to take possession over the territory. The ethnogenesis of the Albanians is uncertain; however the first undisputed mention of Albanians dates back in historical records from 1079 or 1080 in a work by Michael Attaliates, who referred to the Albanoi as having taken part in a revolt against Constantinople. At this point the Albanians were fully Christianised. Few years after the dissolution of Arbanon, Charles of Anjou concluded an agreement with the Albanian rulers, promising to protect them and their ancient liberties. In 1272, he established the Kingdom of Albania and conquered regions back from the Despotate of Epirus. The kingdom claimed all of central Albania territory from Dyrrhachium along the Adriatic Sea coast down to Butrint. A catholic political structure was a basis for the papal plans of spreading Catholicism in the Balkan Peninsula. This plan found also the support of Helen of Anjou, a cousin of Charles of Anjou. Around 30 Catholic churches and monasteries were built during her rule mainly in northern Albania. Internal power struggles within the Byzantine Empire in the 14th century enabled Serbs' most powerful medieval ruler, Stefan Dusan, to establish a