In 1919, at the time of its annexation, the middle part of the County of Tyrol which is today called South Tyrol (in Italian Alto Adige) was inhabited by almost 90% German speakers. Under the 1939 South Tyrol Option Agreement, Adolf Hitler and Benito Mussolini determined the status of the German and Ladin (Rhaeto-Romanic) ethnic groups living in the region. They could emigrate to Germany, or stay in Italy and accept their complete Italianization. As a consequence of this, the society of South Tyrol was deeply riven. Those who wanted to stay, the so-called Dableiber, were condemned as traitors while those who left (Optanten) were defamed as Nazis. Because of the outbreak of World War II, this agreement was never fully implemented. Illegal Katakombenschulen ("Catacomb schools") were set up to teach children the German language.
In 1923, three years after South Tyrol had been formally annexed, Italian place names, almost entirely based on the Prontuario dei nomi locali dell'Alto Adige, were made official by means of a decree. The German name "Tyrol" was banned, likewise its derivants and compound words such as "Tyrolean" and "South Tyrolean". German newspapers, publishing houses, organized clubs and associations, including the South Tyrolean Alpine Club had to be renamed, with the decree said to have been strictly enforced by Italian carabinieri on the ground. The basis for these actions was a manifesto published by Ettore Tolomei on July 15, 1923, called the Provvedimenti per l'Alto Adige ("Measures for the Alto Adige"), becoming the blueprint for the Italianization campaign. Its 32 measures were: