One of the objectives of the collaboration agreement signed in May 2006 between the Regional Ministry of Public Works and Transport and the Casa Medina Sidonia Foundation was the study and reproduction of the documentation stored in the ducal archive about public works and transport.

In order to include the studied documentation in the database, the public works documentation descriptive text had to be adapted, as it was designed to describe 19th and 20th Century construction projects.

The resulting database provides the description and reproduction of documentation about public works dated from the 15th, 16th, 17th and 18th centuries, from the Archive of the Duchy of Medina Sidonia (Sanlúcar de Barrameda, Cadiz).

This type of documentation did not fit the description models used in other archives, because of both their date and nature. Among other reasons, because construction projects are part of an administrative dossier, standard documentation, while the ducal archive documentation is of a private nature. Furthermore, in this case, the investigation was not limited to the Andalusia region.

To create  this database, the manuscript indices of the archive were reviewed to guide the investigator regarding the content of 6,314 ledgers. In most cases, only the first document container in each ledger is described, and based on that 269 ledgers were selected that appeared to be related to public works and transport. Each ledger container a highly variable number of documents, from only one to two or three hundred. These ledgers were studied in detail, selecting 1,321 written documents and 88 plans directly related to public works.

The descriptive sheets were then drafted following ISAD (G) standards. Their main reference is the ledger number, the only signature in use in the archive, so each sheet can describe up to 53 documents related to the same subject. In order to complete the databank with the document’s reproduction, 1,321 written documents and 88 plans were digitised (around 4,100 photographs).

Each document was allocated a two-figure number, the first being the database entry number and the second the order number on the descriptive sheet. For example, document 242_044.pdf corresponds to entry 242, and document number 44 of the descriptive sheet for that entry.