In addition to the monuments and numerous masterpieces of art, the Opera di Santa Maria del Fiore also conserves another inestimable cultural treasure: the Historical Archives. The production and collection of documents has indeed accompanied this prestigious Florentine institution since the beginning of its centuries-old history, making the archive material that today occupies a good part of the Opera offices, the most authentic guideline through the diverse historical epochs in the existence of the Duomo of Florence.

The archives are of a considerable consistence, containing some 7000 pieces including codices of large dimensions, registers, files and loose documents. The material is subdivided into three large sections: the historical archive of the Opera del Duomo, the archive of the credo of baptism of San Giovanni, and the music archive. Substantial portions of these three sections are available on microfilm; several of these, acquired in this format before the 1966 flood, make it possible to read originals that suffered heavy damage.

The archives also include a collection of drawings and prints (XVIII-XX cent. with a few exemplars from earlier epochs) awaiting reorganization, and a photographic archive presently in the inventory phase.

The library, specialized on publications concerning the history of the Opera and its monuments, has now an online catalogue.