The department was created by Article 2 of the decree of 12 November 1810, reuniting the Valais to the French Empire. This decree is written as follows:
NAPOLEON, EMPEROR OF THE FRENCH, KING OF ITALY, PROTECTOR OF THE CONFEDERATION OF THE RHINE, MEDIATOR OF THE SWISS CONFEDERATION:
Considering that the Simplon Road, which unites the Empire to our Kingdom of Italy, is useful to more than sixty million men; that it cost our treasures in France and Italy more than eighteen million, an expense which would become useless if commerce could find there no convenience and perfect security;
That the Valais did not fulfill any of the engagements it had contracted when we had the work begun to open this great communication;
Wanting moreover to put an end to the anarchy which afflicts this country, and to cut short the abusive pretensions of sovereignty of a part of the population on the other,
We have decreed and ordered, decree and order the following:
FIRST ARTICLE. - The Valais is reunited to the Empire.
ART. 2. - This territory will form a department under the name of Department of Simplon.
ART. 3. - This department will be part of the seventh military division.
ART. 4. - It will be taken possession, without delay, on our behalf, and a general commissioner will be in charge of administering it throughout the rest of this year.
ART. 5. - All our ministers will be charged with the execution of this decree.
This decree was confirmed by the organic senatus-consulte of 13 December 1810. This senatus-consulte is written as follows:
FIRST ARTICLE. - The Valais is reunited to the territory of the French Empire.
ART. 2. - It will form a department under the name of Department of Simplon.
ART. 3. - The department of Simplon will have a deputy in the Legislative Body. - This deputy will be appointed in 1811: he will be renewed in the year of the fourth series, to which the Department of Simplon will belong.
ART. 4. - The Department of Simplon will be the jurisdiction of the imperial court of Lyon.
Administration
Prefects
The prefect (préfet) was the highest state representative in the department. The holder of the office was also subprefect of Sion.