The following is taken from JERUSALEM, by F. E. Peters, Princeton Univ. Press, 1985, pp. 189-190. Peters here quotes D. Baldi, ENCHIRIDION LOCORUM SANCTORUM, 1955, pp. 447-448, reprinted, Franciscan Printing Press, Jerusalem, 1982. Baldi gives Eutychius's account from his history of the world, written in 867 C.E., in Arabic, NAZM AL GAWAHIR (Chaplet of Pearls), also known in Latin as ANNALES or EUTYCHII HISTORIA UNIVERSALIS.
"Sophronius is already known to us, and it is the Jerusalem patriarch who quite naturally looms large in two Christian accounts of the same events in Jerusalem in 638. The first, from about A.D. 876, is by the Christian historian Eutychius, the later patriarch of Alexandria, who lived under Islam and was well instructed on the Arab tradition:
"They were Romans when they embraced the Christian religion, and Helena, the mother of Constantine, built the churches of Jerusalem. The place of the rock and the area around it were deserted ruins and they [the Romans] poured dirt over the rock so that great was the filth above it. The Byzantines [Rûm], however, neglected it and did not hold it in veneration, nor did they build a church over it because Christ our Lord said in his Holy Gospel 'Not a stone will he left upon a stone which will not be ruined and devastated.' For this reason the Christians left it as a ruin and did not build a church over it. So Sophronius took Umar ibn al-Khattab by the hand and stood him over the filth. Umar, taking hold of his cloak filled it with dirt and threw it into the Valley of Gehenna. When the Muslims saw Umar ibn al-Khattab carrying dirt with his own hands, they all immediately began carrying, dirt in their cloaks and shields and what have you until the whole place was cleansed and the rock was revealed. Then they all said: 'Let us build a sanctuary and let us place the stone at its heart.' 'No,' Umar responded. 'We will build a sanctuary and place the stone at the end of the sanctuary.' Therefore Umar built a sanctuary and put the stone at the end of it."