In common with the other Aryan races, the ancient Scandinavians recognised, as the basis of their religion, certain supernatural, usually unseen, powers ruling the world and exercising an influence on the affairs of mankind. In the ideas which prevailed as to the nature of these powers certain correspondences can be clearly traced in the various Aryan religions, in spite of the fact that our knowledge of them dates from widely different periods of history. Even the Romans, when they came into contact with the Germanic races, noticed some of the similarities, and applied the names of several of their own deities to the corresponding figures among the barbarian gods. When closer intercourse between Roman and German had established itself, the result of these equations was made prominent in the names adopted by the latter for the days of the week, several of which, in most of the Germanic tongues, still bear witness to the old religion of the race. Thus the counterpart of the Roman _Mars_ was found in the god _Tiw_, and consequently _dies Martis_ was rendered by forms now represented in English by _Tuesday_. In the same way the Roman _Mercurius_, _Jupiter_, and _Venus_ were identified with the Germanic gods called by the English _Wóden_, _Thunor_, and _Fríg_, whence the names of _Wednesday_, _Thursday_, and _Friday_. In making these equations, of course, neither German nor Roman did more than consider the most obvious points of resemblance between the deities; how close the correspondence actually was in each case it is impossible to say, as we know so little of the precise form which the native religion had among the southern Germans. It is only to a certain extent that the details suggested by these translations of the Roman names are supported by the evidence from the Scandinavian side, but it is extremely probable that some of the more striking discrepancies are due to difference in time as well as in place and people.