The new commander, however, was detained in Gaul by insubordination in the army and signs of a revolt among the people, following the death of Augustus, and he did not reach Germany until six years after the defeat of Varus. His march was sudden and swift, and took the people by surprise, for the apparent indifference of Rome had made them careless. The Marsi were all assembled at one of their religious festivals, unprepared for defence, in a consecrated pine forest, when Germanicus fell upon them and slaughtered the greater number, after which he destroyed the sacred trees. The news of this outrage roused the sluggish spirit of all the neighboring tribes: they gathered together in such numbers that Germanicus had much difficulty in fighting his way back to the Rhine. [Sidenote: 15 A. D. THE INVASION OF GERMANICUS.] Hermann succeeded in escaping from his father-in-law, by whom he had been captured and imprisoned, and began to form a new union of the tribes. His first design was to release his wife, Thusnelda, from the hands of Segestes, and then destroy the authority of the latter, who was the head of the faction friendly to Rome. Germanicus re-entered Germany the following summer, A. D. 15, with a powerful army, and to him Segestes appealed for help against his own countrymen. The Romans marched at once into the land of the Cherusci. After a few days they reached the scene of the defeat of Varus, and there they halted to bury the thousands of skeletons which lay wasting on the mountainside. Then they met Segestes, who gave up his own daughter, Thusnelda, to Germanicus, as a captive. The loss of his wife roused Hermann to fury. He went hither and thither among the tribes, stirring the hearts of all with his fiery addresses. Germanicus soon perceived that a storm was gathering, and prepared to meet it. He divided his army into two parts, one of which was commanded by Cæcina, and built a large fleet which transported one-half of his troops by sea and up the Weser. After joining Cæcina, he marched into the Teutoburger Forest. Hermann met him near the scene of his great victory over Varus, and a fierce battle was fought. According to the Romans, neither side obtained any advantage over the other; but Germanicus, with half the army, fell back upon his fleet and returned to the Rhine by way of the North Sea.