BEIJING, May 6  -- Archaeologists working in the 600-year-old Forbidden City, or officially known as the Palace Museum, in Beijing have discovered foundations of buildings from an even earlier dynasty at the site.

Underneath the former royal palace used by the Ming and Qing dynasties (1368-1911) are foundation remains that could be from as early as the Yuan Dynasty (1271-1368), said Li Ji, a senior researcher with the Institute of the Palace Museum.

The palace complex was home to Chinese emperors and was the highest center of power from 1420 to 1911.

Li said the new findings would help understanding of the palace's history and of the layout of ancient Beijing.

The archaeologists also discovered foundations of a previously-unknown construction from the early Ming Dynasty and shards of imperial porcelain believed to have been intentionally buried at the site.