Huge fortress walls protecting the citadel of Sardis, capital of the ancient kingdom of Lydia, have been reported by a Cornell-Harvard archeological group exploring the site.

Alexander the Great conquered the ancient city, once the capital of Croesus, in the fourth century B.C. His successors completed the walls and fortifications.

In attempting to reach the deeply buried archaic city of Sardis, the expedition teams have been digging through layers representing 22 centuries of civilization. Sardis itself was the "Paris" of the ancient world during the sixth and seventh centuries B.C.

One team uncovered an elegant bronze relief of a boar, which exhibits Greek workmanship, a major discovery this season.

A huge areaded hall, perhaps a market hall of the Roman period, is currently emerging from the gymnasium earlier identified by the expedition. Other large buildings have been uncovered by researchers from the University of California, who are digging on the eastern bank of the Pactoius River.

Cornell and Harvard have sponsored the archeological explorations for the last three years. About 150 native workmen are now excavating the six key sites in the huge city.