December 20, 1921: the Kino was established as a public company. The largest stockholder was D. F. Olsen, who also was responsible for the building's construction. With 2100 seats, the Kino was Scandinavia's largest cinema.
July 1, 1929: The Norwegian government bought the Kino, which posed strong competition to existing government-owned cinemas.
1935: Colosseum showed the movie Becker Sharp, the first color film shown in Norway.
July 1, 1948: the Kino was transferred into the ownership of Oslo Kinematografer.
1954: Colosseum is the first Norwegian cinema to install the CinemaScope format. The first movie to be shown in this format is Men jeg så ham dø (The Robe).
1958: the three-projector Cinemiracle system was installed. The first movie screened on this system at the Kino was Windjammer.
1960: 70mm was installed. The new decade was celebrated with a newly refurbished entrance hall, and the movie South Pacific was screened in 70mm. Until now Colosseum had approximately 1250 seats.
February 15, 1963: a major fire shut down the Kino temporarily. Restoration work began immediately under the supervision of architect Sverre Fehn. After another minor fire on the roof and a work accident, the theatre reopened.
September 12, 1964: Colosseum reopens with 1158 seats,......