Spanish archaeologists have made a sweet discovery.

A group of excavators has uncovered a medieval structure in a Barcelona building that was later used as a chocolate factory.

The building dates back to the 19th century, but the walls and doors on the property show that the original structure was much older, according to a press release issued on Feb. 12 by the Barcelona Archaeology Service, which was written in Catalan.

The building is located in Barcelona’s Plaça de la Llana, a medieval plaza.

Its name means “plaza of the wool” in Catalan, as the square was used as a marketplace.

Historians were able to find lead plates that were used in the 19th century chocolate factory. (Barcelona Archaeology Service/Global Geomática, SL/ICUB/ Marta Lucas)

“Although the current estate dates from the 19th century, the parietal archeology work carried out so far has allowed the documentation of walls with arches and doors attributable to a large medieval house of the 14th century,” the translated press release said.

The exact age of the original building is unknown — but if it was built in the 14th century, it could be anywhere from 625 to 725 years old.

Experts believe that the 14th century house was later converted into a hostel in the 15th century.

The medieval house “would have ceased to function during the 16th century,” the press release said.

The Barcelona Archaeology Service said that the original house was later converted into a hostel in the 15th century. (Barcelona Archaeology Service/Global Geomática, SL/ICUB/ Marta Lucas)

The owner of the property in the 16th century would “carry out a major reform to adapt it to the style and fashions of the time,” the Barcelona Archaeology Service said.

Archaeologists found that the house was later divided into three properties in the 18th century.

The group of historians uncovered a set of seven ceramic containers from that time period.

Archaeologists found these 18th century containers during their excavation, and tests will be run on them. (Barcelona Archaeology Service/Global Geomática, SL/ICUB/ Marta Lucas)

The archaeologists plan to run tests on the containers to determine their contents.

In the early 19th century, the building “was occupied by a workshop where chocolate was made,” the press release said.

The factory was called the Clemente Guardia chocolate factory, and excavators found lead plates that were used to make labels at the time.

Archaeologists in Spain found that a 14th medieval structure was originally on the site of a current building. (Barcelona Archaeology Service/Global Geomática, SL/ICUB/ Marta Lucas)

“Work continues on the archaeological excavation of the subsoil and, at the same time, the study of the building’s facings is carried out with the aim of continuing to document the different periods and learn about the evolution of the building,” the translated press release concluded.