"Drouet’s IX Corps, 1810-1811" Topic

Looking through the literature, I haven't found much about this short-lived formation, which joined the Army of Portugal shortly before Fuentes d'Onoro, and was disbanded later that year when Marmont reorganized the army.

It does, however, appear to have been taken almost entirely from Oudinot's old II Corps which fought in the 1809 campaign. Most of the IX Corps units were 4th battalions that had previously belonged to II Corps, and Conroux and Claparede, the division commanders, had previously commanded those same units in II Corps. Some of the 4th battalions and the Tirailleurs Corses and du Po were clearly reassigned, but otherwise, IX Corps looks essentially like II Corps.

Does anyone know anything about the history of the administrative process of transmutation? And was "Drouet," the IX Corps commander, the officer who is usually referred to as "Drouet d'Erlon" in accounts of Waterloo?

Yes, I'm sure it was D'Erlon and I agree that many elements of Oudinot's II Corps in the 1809 campaign appear to be in IX Corps in the Peninsula. Not sure where you would find info on the admin process for disbanding the II Corps into other bodies. A fairly dry historical piece if it was written up! What's clear is that the II Corps in 1809 was three times the size of D'Erlon's Corps in the Peninsula, so not all the units went there. Elements of II Corps went into other Peninsula Corps (i.e. 6th and 25th Legere were in Loison's VI Corps at Fuentes de Onoro) so I think it just got broken up and the units allocated to other formations.

Here some bits from correspondence:

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Here's John Gill's order of battle for Fuentes de Onoro:

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This used to be easier to download, but you can see each of the 12 pages. The notes for the 9th Corps on page 10 reads:

9th Corps had been 2nd Corps of the Army of Germany during the 1809 Franco-Austrian war. Composed of fourth battalions from a host of regiments in response to the urgent requirement to put men in the field against Austria, it was sent to Spain and rebranded as "9th Corps" under GD Drouet d'Erlon. It was essentially a holding formation for its fourth battalions until they could be merged with their home regiments. Those battalions whose parent regiments were part of the Army of Portugal, for example, joined their parent regiments on 27 April 1811 just before the brief Fuentes de Oñoro campaign (6th Léger, 25th Léger, 27th, 39th, 59th, 69th, 76th Ligne). When diverted to assist the Army of Portugal, the corps was en route to the south to join Marshal Soult's Army of the South where its remaining battalions were to be integrated into their parent regiments as well.

@Michael Westman

If you select the PRINT option and then the PRINT TO PDF option you can save the article in a convenient pdf file for future reference.

Thanks Allan.

Yes- I have bought whole books to get the level of detail contained in that OOB paper. It gives some insight into why in some OOBs for Fuentes d'Onoro and Bussaco, French regiments with three battalions are variously listed as having the third or forth battalion present. For example, all of the regiments Michael Westman has listed were in VI Corps, but some are listed in some sources as having 3 battalions (Lipscombe's Atlas generally gives battalion numbers in VI Corps as 1,2, and 4, IIRC) at Bussaco- BUT are also shown as having 3 battalions at Fuentes d'Onoro. What happened? My guess would be that regimental and brigade commanders found three stronger battalions preferable to four weaker ones, and redistributed and cross-leveled their formations when they got reinforcements. A graphic illustration of how much "strategic consumption" affected the army, if each regiment lost a third of its strength or more between the two actions.

"all of the regiments Michael Westman has listed"

Heh, I don't deserve the credit!