Berchtold V. (1186-1218) followed in the steps of his father. He founded and fortified Burgdorf, Moudon, Yverdon, Laupen, Murten, Gümminen, Thun. These towns he founded to be not only places of military strength, but also centres of industry and trade, which should increase the prosperity of his people. But he had, however, to stand against the heavy opposition of the Burgundian nobles. As he was preparing to set out on a crusade with Frederick Barbarossa they rose in arms. Hastening back, he defeated the refractory rebels, both at Avenches and in the Grindelwald valley, in 1191, and immediately after his victories he resumed his strategical projects. On a promontory washed by the Aare, and on imperial crown lands, he raised a new citadel, to which he gave the name of Bern, in memory of Dietrich of Berne (Verona), a favourite hero of Alamannic mediæval poetry.[21] The lesser nobles of the neighbourhood, as well as the humbler people, poured into Bern for shelter, and, receiving a most liberal charter, these burgesses rapidly rose to wealth and power. Being built on imperial land, Bern took from the first a higher standing than the sister town, Freiburg. These city foundations form a chief corner-stone in the fabric of Swiss liberties. Attaining political independence, the towns held their own against aggressors. To effect their deliverance from oppression, they united with kindred communities or with powerful princes, and thus began the system of offensive and defensive alliances. A new enemy arose in the West, and Berchtold V. was defeated by Count Thomas of Savoy (1211), who encroached on Vaud, and seized Moudon. Yet the Zaeringer steadily and successfully strengthened their hold over the country, and obtained the most complete independence. And, indeed, the moment seemed drawing near when Switzerland was to be shaped into a durable monarchical state. However, she was spared that fate--from which no patriotic act of any national hero could probably have rescued her--by a natural, yet providential, event, the extinction of the ducal family. For in 1218 Berchtold V. died, leaving no issue. This century is eminently an age of religious movements. And, although our space will not permit us to enter into full details, yet it is impossible to pass over the great religious revival which centred in the Crusades, that is, so far as that movement touches Switzerland.