The death of Augustus, however, was the signal for mutinous outbreaks among the legions on the European frontiers of the empire; first in Pannonia, then in Germany.  In Pannonia, the ostensible motive was jealousy of the higher pay and easier terms of service of the Praetorian guard.  So violent were the men, and so completely did the officers lose control, that Drusus, the son of Tiberius, was sent to make terms with the mutineers, and only owed his success to the reaction caused by the superstitious alarm of the soldiery at an eclipse of the moon.  Germanicus, who was in command in Germany, was absent in Gaul.  Here the mutiny of the Lower Army, under Caecina, was very serious, because it was clearly organised, the men working systematically and not haphazard.

News of the outbreak brought their popular general, Germanicus, to the spot.  The mutineers at once offered to make him emperor, a proposal which he indignantly repudiated.  The position, in a hostile country, made some concession necessary; but fresh disturbances broke out when it was suspected that the arrival of a commission from the senate meant that the concessions would be cancelled.  Here the reaction which broke down the mutiny was caused by the shame of the soldiers themselves, when Germanicus sent his wife and child away from a camp where their lives were in danger.  Of their own accord, the best of the soldiers turned on their former ringleaders, and slew them.  And the legions under Caecina took similar steps to recover their lost credit.  Germanicus, however, saw that the true remedy for the disaffection would be found in an active campaign.  The desired effect was attained by an expedition against the Marsi, conducted with a success which Tiberius, at Rome, regarded with mixed feelings.

The German tribe named the Cherusci favoured Arminius, the determined enemy of Rome, in preference to Segestes, who was conspicuous for “loyalty” to Rome.  Germanicus advanced to support the latter, and Arminius was enraged by the news that his wife, the daughter of Segestes, was a prisoner.  His call to arms, his declamations in the name of liberty, roused the Cherusci, the people who had annihilated the legions of Varus a few years before.  A column commanded by Caecina was enticed by Arminius into a swampy position, where it was in extreme danger, and a severe engagement took place.  The scheme of Arminius was to attack the Romans on the march; fortunately, the rasher counsels of his uncle, Inguiomerus, prevailed; an attempt was made to storm the camp, and the Romans were thus enabled to inflict a decisive defeat on the foe.

It was at this time that the disastrous practice was instituted of informers bringing charges of treason against prominent citizens on grounds which Tiberius himself condemned as frivolous.  The emperor began to make a practice of attending trials, which indeed prevented corrupt awards, but ruined freedom.