Several military units have been known as the Belgian Legion. The term "Belgian Legion" can refer to Belgian volunteers who served in the French Revolutionary Wars, Napoleonic Wars, Revolutions of 1848 and, more commonly, the Mexico Expedition of 1867.
The first Belgian and Liégeois legions were formed in 1792 from volunteers who had come to serve the First French Republic from the Austrian Netherlands and the Prince-Bishopric of Liège respectively. It was in one of these units that General Louis Joseph Lahure undertook his first military service.
Temporarily regaining control of the Southern Netherlands, on 2 March 1814, Austria formed several military units from regional recruitment. This volunteer force was known as the Légion belge (Belgian Legion) and initially was intended to strengthen the Austrian position in their former provinces in the event of a counterattack from France. With the full occupation of the Southern Netherlands by Austria, Prussia and the United Provinces (Holland), a provisional government was established under the Duke of Beaufort and local levies continued to be recruited separately by each of the three allies. The largest of these was the Belgian Legion which, under the command of the Belgian born Austrian General Count von Murray, was now intended to keep local order. Administrated by the Baron Poederlé, secretary general for armaments, this Legion was made up of 4 line infantry regiments (from Brabant, Flanders, Hainaut and Namur), a light infantry regiment, two cavalry regiments and an artillery regiment.