It is also reported in the name of the Alexandrian Bishop Eutychius (932-940 CE) that the rock known as the Temple Mount had been a place of ruins as far back as the time of the Empress Helena, mother of Constantine the Great, who built churches in Jerusalem. The Byzantines, he said, had deliberately left the ancient site of the Temple as it was, and had even thrown rubbish on it, so that a great heap of rubble formed. It was only when Omar marched into Jerusalem with an army that he asked Kaab, who was Jewish before he converted to Islam, Where do you advise me to build a place of worship? Kaab indicated the Temple Rock, now a gigantic heap of ruins from the temple of Jupiter. The Jews, Kaab explained, had briefly won back their old capital a quarter of a century before (when Persians overran Syria and Palestine), but they had not had time to clear the site of the Temple, for the Rums (Byzantines) had recaptured the city. It was then that Omar ordered the rubbish on the Ṣakhra (rock) to be removed by the Nabataeans, and after three showers of heavy rain had cleansed the Rock, he instituted prayers there. To this day, the place is known as ḳubbat es ṣakhra, the Dome of the Rock.