L'union sacrée was a political truce in France in which the left-wing agreed, during World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

, not to oppose the government nor to call any strike

Strike action

Strike action, also called labour strike, on strike, greve , or simply strike, is a work stoppage caused by the mass refusal of employees to work. A strike usually takes place in response to employee grievances. Strikes became important during the industrial revolution, when mass labour became...

. Made in the name of patriotism

Patriotism

Patriotism is a devotion to one's country, excluding differences caused by the dependencies of the term's meaning upon context, geography and philosophy...

, it opposed the French Section of the Workers' International's (SFIO) internationalism

Internationalism (politics)

Internationalism is a political movement which advocates a greater economic and political cooperation among nations for the theoretical benefit of all...

 and its late former leader Jean Jaurès

Jean Jaurès

Jean Léon Jaurès was a French Socialist leader. Initially an Opportunist Republican, he evolved into one of the first social democrats, becoming the leader, in 1902, of the French Socialist Party, which opposed Jules Guesde's revolutionary Socialist Party of France. Both parties merged in 1905 in...

' pledge not to enter any "bourgeois war." Although an important part of the socialist movement joined the Union sacrée, some trade union

Trade union

A trade union, trades union or labor union is an organization of workers that have banded together to achieve common goals such as better working conditions. The trade union, through its leadership, bargains with the employer on behalf of union members and negotiates labour contracts with...

ists such as Pierre Monatte

Pierre Monatte

Pierre Monatte was a French trade unionist who worked in the printing industry . He was the responsible of the Confédération générale du travail at the beginning of the 20th century, and founded its journal La Vie ouvrière on 5 October 1909...

 opposed it.

On the first of August, 1914, the President of the French Republic

President of the French Republic

The President of the French Republic colloquially referred to in English as the President of France, is France's elected Head of State....

, Raymond Poincaré

Raymond Poincaré

Raymond Poincaré was a French statesman who served as Prime Minister of France on five separate occasions and as President of France from 1913 to 1920. Poincaré was a conservative leader primarily committed to political and social stability...

, declared war on Germany. Three days later, Prime Minister

Prime Minister of France

The Prime Minister of France in the Fifth Republic is the head of government and of the Council of Ministers of France. The head of state is the President of the French Republic...

 Rene Viviani

René Viviani

Jean Raphaël Adrien René Viviani was a French politician of the Third Republic, who served as Prime Minister for the first year of World War I. He was born in Sidi Bel Abbès, in French Algeria. In France he sought to protect the rights of socialists and trade union workers.-Biography:His...

 made a speech:

("In the coming war, France will be heroically defended by all its sons, whose sacred union will not break in the face of the enemy").

This political movement may have been an attempt to create solidarity during a time when the largely pacifist French Socialist Party threatened a general strike, while many French Catholic

Catholic

The word catholic comes from the Greek phrase , meaning "on the whole," "according to the whole" or "in general", and is a combination of the Greek words meaning "about" and meaning "whole"...

s felt slighted by a 1905 law separating Church and State

1905 French law on the separation of Church and State

The 1905 French law on the Separation of the Churches and State was passed by the Chamber of Deputies on 9 December 1905. Enacted during the Third Republic, it established state secularism in France...

. Elements of nationalism (see "August Madness" in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

), anti-German propaganda

Propaganda

Propaganda is a form of communication that is aimed at influencing the attitude of a community toward some cause or position so as to benefit oneself or one's group....

 and a desire to regain the former French territory of Alsace-Moselle

Alsace-Moselle

The territory of the former Alsace-Lorraine, commonly known as Alsace-Moselle, is a region in the eastern part of France, bordering with Germany. Its principal cities are Metz and Strassburg. Alsace-Moselle was part of the German Empire from 1871 to 1918, and again from 1940 until its liberation by...

may have provided further impetus for the movement.