Dortmund refused to become an Imperial Free City.
The first time Dortmund was mentioned in official documents was around 882 as Throtmanni  In throtmanni liber homo arnold[us] viii den[arios] nob[is] soluit [solvit]
As of 2012, Dortmund had a population of 571,403 of whom about 177,000 (roughly 30%) were of non-German origin

