Costumes were one of the keys to her success. Adelaide Ristori was the first Italian actress to take great care of her stage dresses and to make them part of a coherent aesthetic project. This happened at a time when it was customary to reuse the same costumes for many performances, with only minimal adaptations. Her stage costumes, carefully designed by painters and artists and made by the best tailors of the time, set a new standard for historical realism in acting.

Thanks to Adelaide, the theatrical costume stopped being a mere accessory and became a co-actor, part of the actress's dramaturgy and an indispensable tool for the performance’s success. It was through the study and design of costumes that the actress got into character and built her personality, just as it was her costume that immediately captured the spectators' attention, stimulating the process of identification with the character on stage.

Her intuition to rely on the first fashion houses, thus entering a relationship with the emerging haute couture, made Adelaide unique. The happy encounter happened with Charles Frederick Worth, a leading English couturier, who brought the strategies of the fashion system to Paris. Adelaide Ristori entrusted him with the construction of her stage image, thus becoming one of the first actresses in the world to be also recognised as a style icon.

Adelaide Ristori's collection is quite unique because of the fragility of the costumes, which barely survived wear, decay, and the passage of time. The beauty of the clothes, the fine fabrics, the refinement of the workmanship, the overall sartorial quality, and the uniqueness of the pieces (exceptionally accompanied by shoes, jewellery, and stage accessories) make this legacy truly extraordinary.