Socialist Youth International (in German

German language

German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....

: Sozialistische Jugend-Internationale, French

French language

French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

: L'Internationale de la Jeunesse Socialiste) was an international union of socialist youth organisations. It was founded in Hamburg

Hamburg

-History:The first historic name for the city was, according to Claudius Ptolemy's reports, Treva.But the city takes its modern name, Hamburg, from the first permanent building on the site, a castle whose construction was ordered by the Emperor Charlemagne in AD 808...

 1923, through the merger of the Young Workers' International

Young Workers' International

Young Workers' International was an international union of socialist youth organizations. It was founded in at a conference in Amsterdam May 12-May 13, 1921. It functioned as the youth wing of the remnants of the Second International...

 and the International Community of Socialist Youth Organisations

International Community of Socialist Youth Organisations

International Community of Socialist Youth Organisations was an international union of socialist youth organizations. It was founded in February 1921. It functioned as the youth wing of the International Working Union of Socialist Parties...

. The formation of SYI was parallel to what of the Labour and Socialist International

Labour and Socialist International

The Labour and Socialist International was an international organization of socialist and labour parties, active between 1923 and 1940. The LSI was a forerunner of the present-day Socialist International....

, and LSI and SYI were closely connected.

The headquarters of SYI were set up in Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

. In 1933 it shifted to Prague

Prague

Prague is the capital and largest city of the Czech Republic. Situated in the north-west of the country on the Vltava river, the city is home to about 1.3 million people, while its metropolitan area is estimated to have a population of over 2.3 million...

, and in 1938 to Paris

Paris

Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

.

During the Second World War SYI became dormant. It was later replaced by the International Union of Socialist Youth

International Union of Socialist Youth

The International Union of Socialist Youth encompasses socialist, social democratic and Labour Party youth organizations from more than 100 states of the world...

.