The Kingdom of Westfalia was created by Napoleon in December 1807 following the treaty of Tilsit. The new Kingdom was composed of parts of Hannover, Brunswick, Saxony and most of Hesse-Kassel. Westfalia was entered as a charter member of the newly formed Confederation of the Rhine. As such it was obliged to provide a 25,000 strong contingent to the Grande Armee in the event of war. The Westfalian army created to meet this requirement was closely modelled on that of France and by the end of 1808 comprised the royal garde grenadier and jäger battalions, the chevau-leger regiment and a garde-du-corps squadron. The line consisted of an elite jäger-carabinier battalion (normally attached to the Garde), six line infantry regiments each of two battalions, one light battalion, one cuirassier regiment, one chevau-leger regiment plus national guards and veterans units. In July of 1808 the 2nd cuirassier, 7th and 8th Line infantry regiments and the 2nd light infantry battalion were raised. In 1810 the 1st and 2nd hussar regiments were raised, in 1811 the 3rd light infantry battalion and two line infantry regiments (2nd and 7th) added a third field battalion. In 1812 a new two battalion garde infantry regiment (fusiliers) was raised, together with the 9th line regiment, the 4th light battalion and the 2nd chevau-leger regiment. Following the disastrous retreat from Russia less than 1,000 Westfalian survivors gathered at Thorn during January 1813. During 1813 most of the old units were hastily re-raised, the 1st line infantry regiment formed part of the garrison of Danzig and surrendered on 29th November 1814. The 2nd & 3rd regiments and the 2nd light battalion were part of the garrison of Dresden which surrendered when that town fell. The 4th and 5th line infantry regiments were captured at the fall of Kustrin. The 6th line infantry regiment was not re-raised after 1812. The 7th line infantry regiment was disbanded at the dissolution of the Kingdom. The 8th & 9th line infantry regiments, the 1st and 4th light battalions and the fusilier-garde regiment were disbanded after the battle of Leipzig in October 1813. The 1st and 2nd hussars went over to the Austrians on the night of 22/23 August 1813. The garde-du-corps squadron, the grenadier-garde, jäger-garde, chevau-legers-garde, the jäger-carabinier and 3rd light battalions, the 1st chevau-legers and the 1st & 2nd cuirassiers were all in Westphalia and disbanded when the end of the Kingdom came in September 1813.

During the period 1808 - 1813 five different patterns of flag were issued to the line and garde infantry regiments ( the light battalions apparently were not issued flags) and four different patterns of standard were issued to the line and garde cavalry regiments.