As the Nassau duchy joined the allies in 1813, the duke had to raise a new infantry regiment to fulfil his military obligations. As the 1st Infantry Regiment was imprisoned in French camps, the vacant number 1 was taken over by the new third regiment.
Moreover the duke - as others Germans rulers - called upon volunteers to raise a Landwehr infantry regiment and a voluntary Jaegers and Landsturm corps.
As for him, the prince of Orange raised in his German territory an infantry regiment and two voluntary Jaegers companies. As king of Netherlands, he transferred these units in the Dutch army and signed with the duke of Nassau a convention to take the 2nd Nassau Infantry Regiment just coming back from Spain in Dutch service.
The Nassau Infantry regiments were reorganized before the Belgium campaign and established at two line and one Landwehr battalions. Considered as light infantry battalions, each is composed of one grenadier, one flankers and four jaegers companies.

Nassau infantry regiment

Fusiliers
As before. In Dutch service the black cockade is replaced by the orange one.

Grenadiers
As before. Grenadiers of the 1st Infantry Regiment wear scarlet wings instead of epaulets.

Flankers
As before. Flankers of the 1st Infantry Regiment wear yellow wings instead of epaulets.

Officers
As before. In Dutch service the gorget is replaced by an orange silk scarf..

Drummers
As before. The six chevrons on sleeves are replaced by three chevrons on forearms trimmed with yellow embroideries.

Landwehr
As line soldiers but red piping instead of yellow ones and white metal buttons instead of brass ones. Black leatherwork.

Regiment Oranje-Nassau Nr.28

Fusiliers

• Single breasted short tailed coat in dark blue cloth closed by a row of 9 buttons. Dark red collar. Blue shoulder straps trimmed red. Front of coat piped in red. Red cuffs with blue piped red flaps. Red turnbacks. White metal buttons.
• Grey overalls over dark grey gaiters.
• Black felt shako with black leather top and bottom bands, bearing a white metal hexagonal plate stamped with the royal W cipher. White pompon over orange cockade. White cords and flounders. Black leather peak and white metal chinscales.
• White leatherwork.

Officers
Other ranks’ dress with long tails, all white or white metal ornaments become silver or silvered. Silver rank epaulets on shoulder. Orange silk scarf. Grey breeches and black light boots.