But the fact of the mixture must never be lost sight of. Without it, Babylonian religion, like the Babylonian system of writing, would be a hopeless puzzle. We could, indeed, draw up long lists of obscure deities with unmeaning names, and enumerate the titles which the inscriptions give them, but any attempt to trace their history or discover the religious ideas of which they are the expression, would be impossible. We must know what is Semitic and what is Sumerian, or what is due to a combination of the two elements, before we can penetrate to the heart of the old Babylonian theology, and ascertain the principles on which it rests. The native writers themselves were aware of this, and fully realised the fact that Sumerian conceptions of the godhead formed the background of the official faith. But their uncritical efforts to solve the problem of the origin of their religion have added only to the complication of it. Just as the English lexicographers of a past generation found a Greek or Latin derivation for the Teutonic words of our language, so the scholars of Babylonia discovered Sumerian etymologies for Semitic words and divine names, or else assimilated them to other words of a different origin. Thus the Semitic word _Sabattu_, “Sabbath,” is derived from the Sumerian _sa_, “heart,” and _bat_, “to cease” or “rest,” and interpreted as “a day of rest for the heart”; while _pardêṡu_, “paradise,” is explained as the _par_ or “domain of the god Eṡu.”(213) In many cases it is as yet impossible to tell whether a native etymology really rests on a fact of history, or is the invention of learned pedantry or popular etymologising. Marduk or Merodach, for instance, is variously derived from the Sumerian Amar-utuki, “the heifer of the sun-spirit”; and the Semitic Mar-Eridugga, “the son of the city Eridu.”(214) The first etymology is certainly false; our present materials do not allow us to speak so positively in regard to the second. All we can say about it is that it is unlikely in the extreme. And yet a good deal turns upon the true origin of the name of the patron god of Babylon. If it is Semitic, the foundation of the city and of the temple around which it was built would presumably belong to Semitic days, and the development of the cult of the god would be Semitic from the first. The identification of Merodach, moreover, with Asari the son of Ea of Eridu, would receive substantial support; the “son of Eridu” would naturally be the son of the god of Eridu, and we should have to see in Babylon a colony from the old seaport of the Babylonian plain.