The Ottoman–Habsburg War (1683–1699), the subsequent flight of a substantial part of the Serbian population in Kosovo to Austria and the reprisals and looting during the Ottoman counteroffensive led to an influx of Albanian Muslims into Kosovo, northern and northwestern Macedonia. Being in the position of power, the Albanian Muslims managed to push out their Christian neighbours and conquered additional territories in the 18th and the 19th centuries. Pressures from central government following the first Russo-Turkish war that ended in 1774 and in which Ottoman Greeks were implicated as a "fifth column" led to the a superficial islamization of several thousand Greek-speakers in western Macedonia. These Greek Muslims retained their Greek language and identity, remained Crypto-Christians, and were subsequently called Vallahades by local Greek Orthodox Christians because apparently the only Turkish-Arabic they ever bothered to learn was how to say "wa-llahi" or "by Allah". The destruction and abandoning of the Christian Aromanian city of Moscopole and other important Aromanian settlements in the southern Albania (Epirus-Macedonia) region in the second half of the 18th century caused a large-scale migration of thousands of Aromanians to the cities and villages of Western Macedonia, most notably to Bitola, Krushevo and surrounding regions. Thessaloniki also became the home of a large Jewish population following Spain's expulsions of Jews after 1492. The Jews later formed small colonies in other Macedonian cities, most notably Bitola and Serres.