Zoe died in 1050, and Constantine IX. in 1054. On his death, Zoe’s sister Theodora, the last of the Macedonians, became Empress. Though old, she was strong and vigorous, and her long incarceration in a cloister gave her monastic virtues that contrasted strangely with the dissolute habits of Zoe. During her reign of three years the Empire enjoyed at least peace and repose. Her death in 1057 ended not ingloriously the famous dynasty that had since the days of Basil I. held the imperial throne. A new period of trouble now sprang from disputed successions and weak Emperors, at a time when the growth of the Seljukian power threatened the very existence of the Empire. [Sidenote: Rise of the Seljukian Turks.] The Turkish or Mongol tribes of Central Asia had long troubled from time to time the tranquillity of Europe. Among them were Attila and his Huns, but these fierce marauders passed away without leaving any permanent traces of their influence. Of the same stock were the Magyars, who, in 895, finally settled in Pannonia, and the Bulgarians, who, as we have seen, had even earlier taken possession of a large part of the Balkan peninsula. But the Magyars and Bulgarians by accepting Christianity made themselves permanent members of the European commonwealth. While Mongolian invasions such as these disturbed from time to time the peace of eastern Europe, similar invasions had terrified all the civilised nations of Asia as far as the Chinese frontier. But it was the Caliphate in its decline that began to stand in the most intimate relations with the Turks. The growing anarchy of the Arab Empire offered to the Turks a career as mercenaries, and a field for plunder and devastation. As the reward of their services, the Caliphs gave them what they could conquer from the Christians on the eastern frontiers of the Empire. A large Turkish immigration soon peopled the marches of the Caliphate with the fierce warriors from the north. As the Caliphs declined in power, the Turkish condottieri chieftains grew discontented with their pay, and set up military despotisms on their own account. Many of the petty states that grew out of the dissolution of the Caliphate had, like the Ikshidites in Syria, Turkish lords, and were kept together by Turkish arms. Early in the eleventh century the period of transition was over. The Turks became converts to Islam, and religious enthusiasm bound together their scattered tribes and directed their aims. A great Turkish invasion plunged all Asia in terror. In the extreme east Turks or Tartars established at Peking a Manchurian kingdom for northern China (1004). In the very same year, Mahmoud of Ghazni set up a great Turkish state in Afghanistan and India. A generation later, the Turks of the house of Seljuk began to threaten the thrones of western Asia.