The centre of this civilisation was the province of ‘Iráq (Babylonia), with its renowned metropolis, Baghdád, 'the City of Peace' (_Madínatu ’l-Salám_). Only here could the ‘Abbásids feel themselves at home. "Damascus, peopled by the dependants of the Omayyads, was out of the question. On the one hand it was too far from Persia, whence the power of the ‘Abbásids was chiefly derived; on the other hand it was dangerously near the Greek frontier, and from here, during the troublous reigns of the last Omayyads, hostile incursions on the part of the Christians had begun to avenge former defeats. It was also beginning to be evident that the conquests of Islam would, in the future, lie to the eastward towards Central Asia, rather than to the westward at the further expense of the Byzantines. Damascus, on the highland of Syria, lay, so to speak, dominating the Mediterranean and looking westward, but the new capital that was to supplant it must face east, be near Persia, and for the needs of commerce have water communication with the sea. Hence everything pointed to a site on either the Euphrates or the Tigris, and the ‘Abbásids were not slow to make their choice."[480] After carefully examining various sites, the Caliph Manṣúr fixed on a little Persian village, on the west bank of the Tigris, called Baghdád, which, being interpreted, means 'given (or 'founded') by God'; and in A.D. 762 the walls of the new city began to rise. Manṣúr laid the first brick with his own hand, and the work was pushed forward with astonishing rapidity under his personal direction by masons, architects, and surveyors, whom he gathered out of different countries, so that 'the Round City,' as he planned it, was actually finished within the short space of four years. [Sidenote: Despotic character of ‘Abbásid rule.] [Sidenote: The Vizier.]