The Royal Alcazar of Guadalajara is an Andalusian stronghold in the city that dates back to the 9th century and has been transformed into a palace, a sarguette factory, and a military barracks over the centuries.

Near the Alamn ravine and the ancient route to Madrid, it creates a walled enclosure of somewhat more than a hectare in size. Since its inception, it has stood close to the Bradamarte gate on Guadalajara's western side, dividing the Alcallera or Cacharreras artisan sector from the rest of the city. As an Andalusian fortress, its primary role is to guard the entry to the city and to keep an eye on traffic going through the valley of the River Henares and the surrounding countryside. It was a royal palace during the Christian era, similar to the Real Alcázar of Seville and the Alcázar of Córdoba, which were built about the same time, but it was abandoned and turned into a sergeant factory and then military barracks before being destroyed in 1936. Archaeological digs and investigations have been going on since 1998, peeling back the strata to expose the specific rooms from each era.

Since 1998, archaeologists and excavators have worked to piece together the history of the Royal Alcazar of Guadalajara, uncovering four distinct eras of construction: the Andalusian Alcazar, the Mudejar palace, the cloth factory, and the San Carlos barracks.

In 1996, with thoughts of constructing a theatre there, it was decided to conduct an archaeological study of the stronghold. Initial investigations cautioned against construction due to the potential for significant archaeological artefacts to reside there; this proved to be the case. The Royal Alcazar of Guadalajara then became the site of a number of archaeological excavations.

Through an employment workshop, the first excavations were conducted at the Alcázar between 1998 and 2001, revealing the earliest vestiges of the late mediaeval palace, including ornamental elements and the initial constructions, and the stables were consolidated.

The City Council of Guadalajara entrusted Dr. Julio Navarro Palazón of the CSIC's School of Arab Studies with the Alcazar research project in 2004. Two separate campaigns, one running from August 2005 to December 2005 and the other from July 2006 to January 2007, were used to complete the project. In order to get the site ready for the following expedition, a general cleaning of the remains was done during the first campaign, and the distribution of the Mudejar palace was also analysed on an ad hoc basis. During this initial operation, archaeologists uncovered numerous vessels and toys dating back to different eras when the Alcazar was inhabited. The Peso de la Harina was cleaned and the monument was readied for public viewing during the second phase, which also saw the consolidation of any walls or ruins that needed it.