On September 21, 1792, the National Convention met for the first time at the Tuileries in Paris, and its first substantive act was to abolish the monarchy. The motion was put in the afternoon session, there was no debate worth the name, and the vote was unanimous. A deputy from the Paris delegation had already proposed that the word king be struck out of the constitution. France was a republic.
It had taken three years to get there and six weeks to make it unavoidable. The revolution of 1789 had made Louis XVI a constitutional monarch, and he had remained one after the march on Versailles and the flight to Varennes in June 1791. What broke him was the war. The Legislative Assembly declared war on Austria in April 1792, the Prussians and emigres advanced, and on August 10 a rising in Paris, organised through the sections and the fÊdÊrÊs from Marseille, stormed the Tuileries and massacred the Swiss Guard. The Assembly suspended the king.
The elections that produced the Convention were held in early September, by universal male suffrage, in the atmosphere of the September Massacres, in which between 1,100 and 1,400 prisoners in Paris were killed in five days. Turnout was low. The Convention was more radical than the Assembly it replaced, and it was dominated, at least at first, by men who had not wanted the war and then had got it.
The abolition was the easy part. What the Convention could not settle was what to do with the king, and the argument ran through the autumn: the Girondins wanted to avoid executing him, the Montagnards wanted a trial, and in November evidence of Louis's secret correspondence was found in an iron chest in the Tuileries, which settled it. He was tried from December 10, convicted on January 15, and guillotined on January 21, 1793.
The republic declared on September 22, 1792, because the Convention dated its acts from the day after the abolition, and it gave its name to a new calendar. It lasted in one form or another until Napoleon made himself emperor in 1804. It was restored in 1848 and again in 1870, and the Third Republic is the one that lasted, from 1870 to 1940. The Convention itself sat until 1795, through the Terror, and sent about 17,000 people to the guillotine and perhaps 300,000 to prison.