Fifteenth century ruins of a hospital have been unearthed during the construction of Apple's new flagship store in Madrid, reports the Spanish news site El Pais.

Apple's Madrid retail store covering 6,000 square metres, is reportedly being built above the ruins of the Buen Suceso Hospital and its massive floor space is expected to exceed even that of the company's iconic Fifth Avenue store in New York.

The hospital, which was used to treat plague victims, was demolished in 1854.

The Madrid retail store is reportedly Apple's eleventh store in Spain and the fourth in the capital, which is located at No 1, Puerta del Sol (formerly the Paris Hotel).

The hospital's outer walls stand next to a ruined church. Both the buildings were reportedly demolished in 1854 to make room for the square.

According to the report, the ruins of the church were initially found during construction of the Sol Metro and Cercanias light rail station in June 2009. The rail project was then halted for ten months as archaeologists excavated and studied the ruins.

Apple has secured the permission of the director of Madrid's heritage department, Jaime Ignacio Munoz, to proceed with its store on the sole condition that the company will modify the store's basement flooring to symbolically reveal the outline of the walls of the ruins.

Munoz, in a press statement to El Pais, said: "We're not surprised to find these remains because we knew they could be there. The building is located on a historic site and is protected as an area of public cultural interest, so that any action on the ground has to have the approval of the heritage department."

Though there is no word on the Madrid Apple store's opening date, it is likely to be ready in time for Christmas, reports El Pais.