moreover, possible that the British section of the _Not._ is of much older date. (4) The elevation of the tyrant Constantine and his crossing into Gaul would seem to have happened in the first half of A.D. 407. This seems to follow from the account in Olympiodorus (fr. 12, ed. Müller). The second half of A.D. 406 is filled by the episodes of Constantine’s predecessors, Marcus and Gratian. Zosimus (who, in regard to the dating, misunderstood Olympiodorus, as was pointed out by Freeman[367]) says that the invasion of Gaul by the Vandals and their fellows was one of the causes of the rebellion in Britain (vi. 3, 1). This cannot be true, if the text is sound in the entry of Prosper Tiro, which states that the Vandals and Alans crossed the Rhine at the end of December A.D. 406.[368] On the other hand, two considerations might tempt us to suspect this notice, namely, the unlikelihood of a migration in the middle of winter, and the existence of two edicts for a levée of provincials _contra hostiles impetus_ dated April 18 and 20 at Ravenna (cp. Hodgkin, i. 739). But neither of these considerations is weighty enough to justify us in assuming without further evidence anything inconsistent with the testimony of Prosper’s MSS. In any case, the crossing of Constantine into Gaul will fall in the year A.D. 407.[369] We can have no doubt that most of the soldiers in Britain accompanied Constantine when he departed to secure Gaul. But he must have left garrisons; it was important for him to retain his hold on the island if, as is probable, his corn supply depended on it. Mr. Freeman has summed up the event thus in its consequences for Britain: “Britain might be saved by a campaign in Gaul. But if this was the motive, the thought of saving Britain must soon have passed away from the minds of Constantine and his soldiers. Whether they cared for such an object or not, the course of things on the mainland soon made it hopeless for them to think of keeping up any relations with the great island. The crossing of Constantine into Gaul thus became the end of the Roman power in Britain” (p. 56). It is possible that Constantine, before he departed, may have set up a colleague, named Carausius, to safeguard his interests in Britain. This at least is the inference drawn by Mr. A. J. Evans from a coin found at Richborough (see _Numismatic Chronicle_, third series, vii. 191 _sqq._ 1887, and App. 19 to Bury’s edition of Gibbon, vol. iii.).