Madrid’s historic Hall of Realms will be refurbished and transformed into an important art exhibition space by architects Foster + Partners and Rubio Arquitectura, after the pair were named winners of an international competition for the project.

The space will form an expansion to the city’s Museo del Prado campus; Spain’s main national art museum. The Hall of Realms building was part of the 17th century Royal Buen Retiro Palace and most recently served as an Army Museum for the city.

The design team will create a new community focus for the city by bringing together the various buildings that comprise the Prado with public spaces and underground links.

Their proposal goes back four centuries to rediscover the original three storey southern façade, which will become the backdrop for “a spectacular new space within the building.”

The existing outer walls will be delicately opened up to bring light and views in from the new civic plaza. A new public route will run through the building, with terrace cafes on the north side.

A new roof will be added harvest energy from integrated solar cells, give natural light to the galleries below and creating a cantilever to protect the southern façade.

“I would like to say how honoured we are to contribute to this next phase of the expansion of the Prado – one of the truly great museums of the world,” said Norman Foster, chair of Foster + Partners. “The Hall of Realms, built by Crescenzi and Carbonel in the 1630s, is one of the very few remains of the former palace and predates the museum which was conceived in 1819.

“Two centuries later the transformation and expansion of this historic hall will add significant new galleries and related public spaces to the Prado. It will also create, as a setting, a new urban focus for the city of Madrid.”