On July 12, 1806 sixteen German states sign a treaty creating the Confederation of the Rhine under Napoleon's "protection." Twenty-five days later, the Holy Roman Empire ceases to exist.
After Austerlitz in December 1805, Napoleon had broken Austrian power in Central Europe. The Holy Roman Empire was already a fiction held together by habit and Habsburg prestige. Napoleon did not need to abolish it directly. He simply made it unnecessary.
Napoleon assumed the title of "Protector of the Confederation" — language carefully chosen to preserve the appearance of member sovereignty while ensuring Paris controlled their foreign policy entirely.
Each member state was obligated to furnish military contingents for the French army. Together they provided Napoleon with approximately 120,000 additional German soldiers — a force that would march with the Grande Armée across Europe, including into Russia in 1812.
The creation of the Confederation was the signal Austria had been dreading. On August 6, 1806 Emperor Francis II laid down the crown of the Holy Roman Empire of the German Nation. The Habsburgs retained the title of Emperors of Austria, but between the Rhine and the Elbe, it was Napoleon's authority that now prevailed. Austria's centuries-long dominance in Germany was over.