Colosse was a small city near Laodicea in Asia Minor, east of Ephesus. It is not mentioned in the record of Paul's travels in Acts. Though Paul lived in the general area for two years, it is not certain that he himself ever preached in Colosse. The church was founded by Epaphas, one of Paul's lieutenants and a native of Colosse (Col 4:12). Paul wrote this letter while imprisoned (Col 4:10, Col 4:18), probably in Rome around 60 AD. This would date it close to the time of Ephesians.
Colossians is a short letter which does not cover the great themes of Christianity. Paul is, instead, writing to counteract a particular local heresy:
See to it that no one takes you captive through hollow and deceptive philosophy, which depends on human tradition and the basic principles of this world rather than on Christ (Col 2:8).
It is not known exactly what cult or doctrine Paul was describing. It contained elements of mysticism as well as legalism, and it denigrated the person and work of Jesus Christ. Paul reiterates the centrality and supremacy of Christ. There are no Old Testament references in the book, and only a little racial teaching.