Ottocar was but little aware of the tremendous energies of the foe he had aroused. Regarding Rhodolph almost with contempt, he had by no means made the arrangements which his peril demanded, and was in consternation when he heard that Rhodolph, in alliance with Henry of Bavaria, had already entered Austria, taken possession of several fortresses, and, at the head of a force of a thousand horsemen, was carrying all before him, and was triumphantly marching upon Vienna. Rhodolph had so admirably matured his plans, that his advance seemed rather a festive journey than a contested conquest. With the utmost haste Ottocar urged his troops down through the defiles of the Bohemian mountains, hoping to save the capital. But Rhodolph was at Vienna before him, where he was joined by others of his allies, who were to meet him at that rendezvous. Vienna, the capital, was a fortress of great strength. Upon this frontier post Charlemagne had established a strong body of troops under a commander who was called a margrave; and for some centuries this city, commanding the Danube, had been deemed one of the strongest defenses of the empire against Mohammedan invasion. Vienna, unable to resist, capitulated. The army of Ottocar had been so driven in their long and difficult march, that, exhausted and perishing for want of provisions, they began to mutiny. The pope had excommunicated Ottocar, and the terrors of the curse of the pope, were driving captains and nobles from his service. The proud spirit of Ottocar, after a terrible struggle, was utterly crushed, and he humbly sued for peace. The terms were hard for a haughty spirit to bear. The conquered king was compelled to renounce all claim to Austria and several other adjoining provinces, Styria, Carinthia, Carniola and Windischmark; to take the oath of allegiance to the emperor, and publicly to do him homage as his vassal lord. To cement this compulsory friendship, Rhodolph, who was rich in daughters, having six to proffer as bribes, gave one, with an abundant dowry in silver, to a son of Ottocar. The day was appointed for the king, in the presence of the whole army, to do homage to the emperor as his liege lord. It was the 25th of November, 1276. With a large escort of Bohemian nobles, Ottocar crossed the Danube, and was received by the emperor in the presence of many of the leading princes of the empire. The whole army was drawn up to witness the spectacle. With a dejected countenance, and with indications, which he could not conceal, of a crushed and broken spirit, Ottocar renounced these valuable provinces, and kneeling before the emperor, performed the humiliating ceremony of feudal homage. The pope in consequence withdrew his sentence of excommunication, and Ottocar returned to his mutilated kingdom, a humbler and a wiser man.