This terrible display of vengeance struck the Protestants with consternation. The extreme Catholic party were exultant, and their chiefs met in a general assembly and passed resolutions approving the course of the emperor and pledging him their support. Ferdinand was much encouraged by this change in his favor, and declared his intention of silencing all Protestant voices. He recalled an army of twenty-four thousand men from Italy. They crossed the Alps, and, as they marched through the frontier States of the empire, they spread devastation and ruin through all the Protestant territories, exacting enormous contributions, compelling the Protestant princes, on oath, to renounce the Protestant league, and to unite with the Catholic confederacy against the King of Sweden. In the meantime, Gustavus pressed forward into the duchy of Mecklenburg, driving the imperial troops before him. Tilly retired into the territory of the Elector of Saxony, robbing, burning and destroying everywhere. Uniting his force with the army from Italy he ravaged the country, resistlessly advancing even to Leipsic, and capturing the city. The elector, quite unable to cope with so powerful a foe, retired with his troops to the Swedish camp, where he entered into an offensive and defensive alliance with Gustavus. The Swedish army, thus reinforced, hastened to the relief of Leipsic, and arrived before its walls the very day on which the city surrendered. Tilly, with the pride of a conqueror, advanced to meet them. The two armies, about equal in numbers, and commanded by their renowned captains, met but a few miles from the city. Neither of the commanders had ever before suffered a defeat. It was a duel, in which one or the other must fall. Every soldier in the ranks felt the sublimity of the hour. For some time there was marching and countermarching--the planting of batteries, and the gathering of squadrons and solid columns, each one hesitating to strike the first blow. At last the signal was given by the discharge of three pieces of cannon from one of the batteries of Tilly. Instantly a thunder peal rolled along the extended lines from wing to wing. The awful work of death was begun. Hour after hour the fierce and bloody fight continued, as the surges of victory and defeat swept to and fro upon the plain. But the ever uncertain fortune of battle decided in favor of the Swedes. As the darkness of evening came prematurely on, deepened by the clouds of smoke which canopied the field, the imperialists were everywhere flying in dismay. Tilly, having been struck by three balls, was conveyed from the field in excruciating pain to a retreat in Halle. Seven thousand of his troops lay dead upon the field. Five thousand were taken prisoners. All the imperial artillery and baggage fell into the hands of the conqueror. The rest of the army was so dispersed that but two thousand could be rallied under the imperial banners.