In the mean time, the usurper Alexius, on flying from Constantinople, had found a retreat in the province of Thrace; several cities opened their gates to him, and a few partisans assembled under his banner. The son of Isaac resolved to seek the rebels and give them battle. Henry of Hainault, the count of St. Pol, and many knights, accompanied him in this expedition. At their approach, the usurper, shut up in Adrianople, quickly abandoned the city and fled away towards Mount Hemus. All the rebels who had the courage to await them, were either conquered or dispersed. But young Alexius and the Crusaders had a much more formidable enemy to contend with: this was the nation of the Bulgarians. These wild and ferocious people obedient to the laws of Constantinople at the time of the first crusade, had taken advantage of the troubles of the empire to shake off the yoke of its rulers.[109] The leader of the Bulgarians, Joannices, an implacable enemy of the Greeks, had embraced the faith of the Church of Rome, and declared himself a vassal of the sovereign pontiff, to obtain from him the title of king. He concealed under the veil of a new religion the most vindictive hatred and aspiring ambition, and employed the support and credit of the court of Rome to make war against the masters of Byzantium. Joannices made frequent incursions into the countries adjoining his own territories, and threatened the richest provinces of the empire with invasion. If young Alexius had been guided by prudent counsels, he would have taken advantage of the presence of the Crusaders to intimidate the Bulgarians, and compel them to remain on the other side of Mount Hemus: this expedition might have deservedly obtained him the confidence and esteem of the Greeks, and assured the repose of several provinces; but whether he was not seconded by the Crusaders, or that he did not perceive the advantages of such an enterprise, he contented himself with threatening Joannices; and, without having made either peace or war, after receiving the oaths of the cities of Thrace, his sole wish was to return to Constantinople.