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The Senate proclaims Napoleon Bonaparte Emperor of the French

On this day · 18 May 1804
40 sec read

A single decree of the Senate transformed France's republic into a hereditary empire — months before the famous coronation.

Verified · The Napoleon Series — Constitution of the Year XII (primary document)

On May 18, 1804 (28 Floréal, Year XII), the French Senate passed a sénatus-consulte declaring that “Napoleon Bonaparte, present First Consul of the Republic, is Emperor of the French.” In a single stroke, the First French Empire was born and the throne made hereditary in the Bonaparte family.

The wording mattered. The title was Emperor of the French, not Emperor of France — sovereignty was framed as flowing from the people rather than from ownership of the land, a republican gloss over an unmistakably monarchical reality.

The empire was made on paper in May; the crown came in December.

The decree, often called the Constitution of the Year XII, was ratified by a plebiscite that summer. The pageantry everyone remembers — Napoleon crowning himself at Notre-Dame with Pope Pius VII looking on — came only on December 2, 1804.

1804
empire declared
Dec 2
coronation

Sources & references

2 references

Well-established. Corroborated by 2 independent sources.

1 The Napoleon Series — Constitution of the Year XII (primary document) primary document “May 18, 1804 (28 Floréal, Year XII) ... Title I, Article 5: 'Napoleon Bonaparte, present First Consul of the Republic, is Emperor of the French.'” napoleon-series.org ↗
2 Treaty of Fontainebleau, April 11, 1814 — official text historical reference “18 May 1804 ... The Senatus-consultum was approved by the Senate unanimously minus three votes [proclaiming Napoleon Emperor of the French].” napoleon-empire.org ↗
✓ Last reviewed Jun 7, 2026

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