The Royal Swedish Opera has in its possession a great number of historical theatre costumes, mostly dating from the late1700s through to the mid 1900s. These costumes have been used in many ballet, opera and theatre productions. Because the Royal Opera and the Royal Dramatic Theatre were together under the name "The Royal Theatres" for approximately 100 years, the opera's current collections contain important material from both theatres. Such historical costumes have proven to be very interesting exhibition material, not only for the general public, but also to students and researchers in theatre, dance and art sciences. The costumes also serve as important reference objects for practicing theatre artists, stage designers, costume designers, costume makers, and as valuable examples of older tailoring techniques. This collection needs to be properly documented. Because the costumes have not been photographed or catalogued, they are not really accessible, nor are they being stored in the favourable conditions usually associated with archived materials. This project, which includes digital photographing, database registration and professional archival storage, will help greatly to make the collection more accessible to researchers and less prone to damage, thereby insuring there future preservation of the collection.