The Transylvanian Saxons (German: Siebenbürger Sachsen; Hungarian: Erdélyi szászok; Romanian: Sași) are a people of German ethnicity who settled in Transylvania (German: Siebenbürgen) from the 12th century onwards.
The colonization of Transylvania by Germans was begun by King Géza II of Hungary (1141–1162). For decades, the main task of the German settlers was to defend the southeastern border of the Kingdom of Hungary. The colonization continued until the end of the 13th century. Although the colonists came mostly from the western Holy Roman Empire and generally spoke Franconian dialects, they were collectively known as Saxons because of Germans working for the Hungarian chancellery.
After 1918, when, following the Treaty of Trianon, Transylvania was separated from Hungary and united with Romania, Transylvanian Saxons, together with other German-speaking groups in newly enlarged Romania (Banat Swabians, Satu Mare Swabians, Bessarabia Germans, Bukovina Germans), became part of the German minority in Romania. The Transylvanian Saxon population has decreased since World War II. Transylvanian Saxons started leaving Transylvania during and after World War II, settling first in Austria, then especially in Germany. The process of emigration continued during Communist rule in Romania, and even into the collapse of the Ceaușescu regime in 1989 when approximately half a million fled to Germany. The great majority of Transylvanian Saxons now live in Germany. A sizable Transylvanian Saxon population also resides today in the United States, notably in Idaho, Ohio and Colorado and in Southern Ontario, Canada. Relatively few still live in Romania, where at the last official census around 37,000 Germans were registered, the number including also Banat Swabians and Sathmar Swabians.