Insula

I´NSULA or F´NSULA ALLO´BROGUM, in Gallia Narbonensis. Livy (Liv. 21.31), after describing Hannibal's passage of the Rhone, says that he directed his march on the east side towards the inland parts of Gallia. At his fourth encampment he came to the Insula, where the rivers Arar and the Rhodanus, flowing down from the Alps by two different directions, comprise between them some tract of country, and then unite: it is the level country between them which is called the Insula. The Allobroges dwell near.One might easily see that there must be some error in the word Arar; for Hannibal could not have reached the latitude of Lugdunum ( Lyon) in four days from the place where he crossed the Rhone; and this is certain, though we do not know the exact place where he did cross the Rhone. Nor, if he had got to the junction of the Arar and Rhodanus, could Livy say that he reached a place near which the Allobroges dwell; for, if he had marched from the Isara ( Isère) to the junction of the Saoneand Rhone, he would have passed through the country of the Allobroges. [ALLOBROGES] Nor does the Arar ( Saône) flow from the Alps, though the Isara does. Besides this, if Hannibal had gone so far north as the part between the Saôneand Rhone, he would have gone much further north than was necessary for his purpose, as Livy describes it. It is therefore certain, if we look to the context only, that we must read Isarafor Arar;and there is a reading of one MS., cited by Gronovius, which shows that Isara may have once been in the text, and that it has been corrupted. (Walekenaer, Géog. &c. vol. 1. p. 135.) Livy in this passage copied Polybius, in whose MSS. (3.49) the name of the river is Scoras or Scaras; a name which the editors ought to have kept, instead of changing it into Isaras (Ἰσάρας), as Bekker and others before him have done, though the Isara or Isèreis certainlv the river. In the latest editions of Ptolemy (Ptol. 2.10.6) the Isara appears in the form Isar (‘Ioeap); but it is certain that there are great variations in the MSS. of Ptolemy, and in the editions. Walckenaer (vol. 1. p. 134) says that the edition of Ulm of 1482 has Sicarus, and that there is Sicarosin the Strassburg editions of 1513, 1520, 1522. The editio princeps of 1475 has Caesar;and others have Tisarand Tisara.The probable conclusion is, that Isc-aris one of the forms of the name, which is as genuine a Celtic form as Is-aror Isara,the form in Cicero ( ad Fam. 10.15, &c.). Isc-aramay be compared with the British forms Isaca(the Exe), Isca, and Ischalis; and Is-ara with the names of the Italian rivers Ausar and Aesis.
Polybius compares the country in the angle between the Rhone and the Isara ( Isère) to the Delta of Egypt in extent and form, except that in the Delta the sea unites the one side and the channels of the streams which form the two other sides; but here mountains almost inaccessible form the third side of this Insula. He describes it as populous, and a corn country. The junction of the Isar, as Strabo calls the river (p. 185), and the Rhone, was, according to him, opposite the place where the Cévennesapproach near to the banks of the Rhone.
The Isère, one of the chief branches of the Rhone, rises in the high Pennine Alps, and flows through the valleys of the Alpine region by a very winding course past St. Maurice, Moutiers, Conflans, Montmeilian, where it begins to be navigable, Grenoble, the Roman Cularo or Gratianopolis, and joins the Rhone a few miles north of Valentia ( Valence). Its whole course is estimated at about 160 miles. Hannibal, after staying a short time in the country about the junction of the Rhone and the Isére, commenced his march over the Alps. It is not material to decide whether his whole army crossed over into the Insula or not, or whether he did himself, though the words of Polybius imply that he did. It is certain that he marched up the valley of the Isèretowards the Alps; and the way to find out where he crossed the Alps is by following the valley of the Isère.
[G.L]