Ramadan Marmullaku noted that, in the 1600s, the Ottomans organized a concerted campaign of Islamization that was not typically applied elsewhere in the Balkans, in order to ensure the loyalty of the rebellious Albanian population. Although there were certain instances of violently forced conversion, usually this was achieved through debatably coercive economic incentives – in particular, the head tax on Christians was drastically increased. While the tax levied on Albanian Christians in the 1500s amounted to about 45 akçes, in the mid-1600s, it was 780 akçes. Conversion to Islam here was also aided by the dire state of the Catholic church in the period— in the entirety of Albania, there were only 130 Catholic priests, many of these poorly educated. During this period, many Christian Albanians fled into the mountains to found new villages like Theth, or to other countries where they contributed to the emergence of Arvanites, Arbëreshë, and Arbanasi communities in Greece, Italy, and Croatia. While in the first decade of the 17th century, Central and Northern Albania remained firmly Catholic (according to Vatican reports, Muslims were no more than 10% in Northern Albania), by the middle of the 17th century, 30–50% of Northern Albania had converted to Islam, while by 1634 most of Kosovo had also converted. During this time, the Venetian Republic helped to prevent the wholesale Islamisation of Albania, maintaining a hold on parts of the north near the coast.