Between 1795 and 1799, the constitution governing France dictated there be an executive arm of government – the Directoire, composed of five Directors. One of these five, Emmanuel Joseph Sieyès, approached General Napoleon Bonaparte in 1799, seeking his support for a coup d'état to overthrow the four year old constitution. Also involved were the Director Roger Ducos, Napoleon's brother Lucien, and diplomat Charles Maurice de Talleyrand-Périgord. It would take place on 9 November 1799 (otherwise known as 18 Brumaire, An VIII, under the French Republican Calendar); the following day, troops led by Napoleon would seize control of France. The legislative councils (Council of Five Hundred and Council of Ancients) were dismissed and a diminished legislature was left, naming Napoleon, Sieyès and Ducos as provisional Consuls to administer government. Sieyès had expected to be the head of this new Consulate; Bonaparte doublecrossed him by drafting the Constitution of the Year VIII and thus secured his own election as First Consul. Consequently, he became the most powerful person in France. This power was soon augmented by the inception of the Constitution of the Year X, making him First Consul for life.
Soon after, Napoleon schemed to acquire total power over the Pope and the Roman Catholic Church. The first step in this plan was implemented at the Battle of Marengo, causing Austria to evacuate much of Italy. Napoleon intended to keep the Duchy of Milan and completely remove any remaining Austrian power over Italy, then begin a new campaign in the East or Egypt. To further his attempt at becoming the master of the Catholic Church, he increased his hold over Italy by uniting Piedmont and planned to annex Genoa, Parma, Tuscany and Naples. In an effort to retain the favor of France's mostly Catholic public, Napoleon instituted the Concordat of 1801; the Catholic Church was now official church of France. This proved a grave error and prevented him from ever having supreme control of the Church.
In January 1804, a plot organised by the European royal House of Bourbon to overthrow Napoleon was uncovered by his secret police. As well as arresting and executing Louis, duc d'Enghien, Napoleon used this to justify the restoration of a hereditary monarchy in France, with himself as Emperor, arguing this would make it impossible for the Bourbons to return. Consequently, the Senate named him Emperor on 8 May 1804. With Pius VII's blessing, Napoleon officially crowned himself Emperor and his wife Joséphine Empress on 2 December. Six months later, on 26 May 1805, the Iron Crown of Lombardy was placed upon Napoleon's head, making him also King of Italy.
Then Napoleon undertook four campaigns to transform his feudal empire into one inspired by Rome. The first of these four campaigns swept away what remained of the Holy Roman Empire and created the Confederation of the Rhine, under Napoleon's control. Napoleon then created the Kingdom of Italy (Napoleonic), annexed Venetia and its ancient Adriatic Empire, and occupied Ancona. He also planned to invade Britain and amassed the best military resources he ever had, La Grande Armée; this plan was never undertaken. The Napoleonic Empire had been formed.