The phenomenon of Islamisation among the Albanians became primarily widespread from the 17th century and continued into the 18th century. Islam offered them equal opportunities and advancement within the Ottoman Empire. However, motives for conversion were, according to some scholars, diverse depending on the context though the lack of source material does not help when investigating such issues. Because of increasing suppression of Catholicism, most Catholic Albanians converted in the 17th century, while Orthodox Albanians followed suit mainly in the following century.