It must always be doubtful whether his attitude at this time was merely assumed in order to lure Decimus Brutus to his destruction, or whether Plancus really remained undecided to the last moment. Decimus during the latter half of May occupied Eporedia, Vercellæ, and Pollentia; he thus commanded the entrance both to the pass through the Cottian Alps (Mont Cenis) and to that through the Graian Alps (Little St. Bernard); by either of these he could join hands with Plancus. From a purely military point of view, Decimus' best course would have been to retreat to the north-east of the Cisalpine province, so as to be able to fall back in the last resort through Illyricum on the support of his namesake in Macedonia. But by such a retreat he would have left Plancus unsupported, and would have sadly discouraged the republicans in Rome. He resolved therefore to cross the Alps, and the two armies seem actually to have effected a junction before Plancus finally deserted the cause. This desertion ended the conflict in the West. Decimus' legions of recruits proved, as he had expected, untrustworthy; they were conscious of their inability to face the veterans, and as soon as these were united against them they submitted without a blow. Their commander attempted to escape eastward, but was overtaken and put to death by Antony's orders early in September.
The revival of the war which they had believed to be ended was a bitter disappointment for the Republicans of Rome. Cicero remained at his post as leader of the House and practical head of the central
