Since the 14th and especially in the 15th century the Ottoman Empire had extended to the Balkans and the Crimea. There were many conversions, particularly in parts of Albania and of Bosnia and Herzegovina.
Map showing the extension of the Ottoman Empire, 2003, unknown creator; source: Wunderer, Hartmann: Der Islam und die westliche Welt: Konfrontation, Konkurrenz, Kulturaustausch, Hannover 2003, p. 115, © Bildungshaus Schulbuchverlage Westermann Schroedel Diesterweg Schöningh Winklers GmbH, Braunschweig.