When were the plaza and moat built in Jerusalem, Israel

The Antonia Fortress was defended from the north by a 164-foot-wide moat which separated the bedrock base of the Antonia from the northern ridge. Herod decided to further quarry a section of the moat in order to form two large cisterns, called Struthion (Greek "sparrow") Pools, which collected rainwater directed from rooftops. Originally the pools were open-air but in 135 AD they were covered over when the emperor Hadrian transformed the area above into a marketplace by constructing two vaults over the pool. For more information see this web site.