To support her regular troops, Austria made extensive use of auxiliary forces during the Revolutionary and Napoleonic Wars. The Balkan Grenzers performed a mix of Military Frontier guard, field army and light roles, and were separated into the National Grenz regiments in 1798. French .migr.s, Belgian and Polish volunteers, German J.ger and Balkan refugees formed volunteer units in the 1790s, which were mostly regularised into Light Battalions (1798-1801).The militia garrison troops of 1800 were developed into the conscript Landwehr of 1808, although volunteers (Freiwillige) joined the field army in 1809. Hungary and Croatia provided traditional Insurrection militias that fought at Raab in 1809. This title examines the different histories, organisation and colourful uniforms of these multi-national troops.