Troisdorf became a free city in 1952. In 1969, the urban area expanded with the annexation of the township of Sieglar and the villages of Altenrath and Friedrich-Wilhelms-Hütte (total population in 1969: about 51,000). The first large settlements in this area go back to the 9th and 10th century (Eschmar and Sieglar 832, Bergheim 987). The first churches in this area were built around 700 AD in Bergheim (St. Lambertus). [citation needed]
Troisdorf is home to about 9,600 foreign nationals. The two most numerous foreign national groups are Turks (3,100) and Greeks (1,600). On June 4, 1972, Troisdorf founded the first advisory council for foreign citizens in Germany. In the years following the Peaceful Revolution and German reunification of 1989/1990 many migrants from Russia and other East European countries settled in Troisdorf.
In April 2014, Troisdorf had a population of 76,435 according to official records.[3] 11% of the population were foreign migrants.
Troisdorf has a predominantly Christian population: Roman Catholics, Protestants, Baptists, Jehovah's Witnesses and other Christian denominations, along with Muslim, Orthodox Christian and Jewish populations of non-indigenous origin. Troisdorf is one of the German cities whose mosque includes a minaret; it was built for the local Islamic community.
Évry-Courcouronnes, France (1972)
Genk, Belgium (1990)
Heidenau, Germany (1990)
Redcar and Cleveland, United Kingdom (1990)
Corfu, Greece (1996)
Nantong, China (1997)
Özdere, Turkey (2004)