short-lived empire that included all of Albania except Durrës. In 1367, various Albanian rulers established the Despotate of Arta. During that time, several Albanian principalities were created, notably the Principality of Albania, Principality of Kastrioti, Lordship of Berat and Principality of Dukagjini. In the first half of the 15th century, the Ottoman Empire invaded most of Albania, and the League of Lezhë was held under Skanderbeg as a ruler, who became the national hero of the Albanian medieval history. Ottoman Empire With the fall of Constantinople, the Ottoman Empire continued an extended period of conquest and expansion with its borders going deep into Southeast Europe. They reached the Albanian Ionian Sea Coast in 1385 and erected their garrisons across Southern Albania in 1415 and then occupied most of Albania in 1431. Thousands of Albanians consequently fled to Western Europe, particularly to Calabria, Naples, Ragusa and Sicily, whereby others sought protection at the often inaccessible Mountains of Albania. The Albanians, as Christians, were considered an inferior class of people, and as such they were subjected to heavy taxes among others by the Devshirme system that allowed the Sultan to collect a requisite percentage of Christian adolescents from their families to compose the Janissary. The Ottoman conquest was also accompanied with the gradual process of Islamisation and the rapid construction of mosques which consequently modified the religious picture of Albania. A prosperous and longstanding revolution erupted after the formation of the Assembly of Lezhë until the Siege of Shkodër under the leadership of Gjergj Kastrioti Skanderbeg, multiple times defeating major Ottoman armies led by Sultans Murad II and Mehmed II. Skanderbeg managed to gather several of the Albanian principals, amongst them the Arianitis, Dukagjinis, Zaharias and Thopias, and establish a centralised authority over most of the non-conquered territories, becoming the Lord of Albania. Skanderbeg consistently pursued the goal relentlessly but rather unsuccessfully to constitute a European coalition against the Ottomans. He thwarted every attempt by the Ottomans to regain Albania, which they envisioned as a springboard for the invasion of Italy and Western Europe. His unequal fight against them won the esteem of Europe also among others financial and military aid from the Papacy and Naples, Venice and Ragusa. When the Ottomans were gaining a firm foothold in the region, Albanian towns were organised into four principal sanjaks. The government fostered trade by settling a sizeable Jewish colony of refugees fleeing persecution