Togrul, the Temporal Chief of the Mohammedan World, dying childless, was succeeded by his nephew Alp Arslan, "the Valiant Lion." As soon as he was seated on the throne, he determined to continue the work of extending his dominion westward at the expense of "the third of the men," whom he very correctly denounced as idolators. "He passed the Euphrates," says Gibbon, "at the head of the Turkish cavalry," A.D. 1063, "and entered Caesarea, the metropolis of Cappadocia, to which he had been attracted by the fame and wealth of the temple of St. Basil." He carried away the doors of the shrine incrusted with gold and pearls, and profaned the relics of the guardian saint.

The final conquest of Armenia and Georgia, began by Togrul, was achieved by Alp Arslan, who by this success gave proof that the power of the Seljukian Turks was no longer "bound by the great river Euphrates," but emphatically "loosed." The loss of this important frontier was the of a day; but as the idolators inhabiting the country were also heretics, the orthodox idolators of the capital were neither surprised nor displeased that they had been abandoned by their deities to the invader. The Turkish sultan and his son Malek were indefatigable in this "holy war;" their captives were compelled to promise both spiritual and temporal obedience; and to wear an iron horse-shoe, as a badge of ignominy, if they still adhered to the daemonial and idol worship of their fathers.

The Turks had penetrated into the heart of Phrygia; and their numerous detachments were scattered over Asia in the security of conquest. These were separately surprised and defeated by the Greeks under their emperor Romanus Disgenes; who, in three laborious campaigns, drove the Turks beyond the Euphrates; and then undertook the recovery of Armenia. The report of this bold invasion brought Alp Arslan again into the field. He flew to the scene of action at the head of forty thousand horse. His hopes of victory were in the arrows of the Turkish cavalry. After wasting the greater part of a summer’s day, fatigue compelled the Greeks and their Latin allies to retire to camp. At this crisis, the Turkish squadrons poured in a cloud of arrows. The destruction of the army followed; the emperor was taken prisoner, and the Asiatic provinces of Rome irretrievably lost. "The third of the men" inhabiting the provinces "were killed." Their sovereignty was abolished, and they became the slaves of the victorious Turks, whose dominion was advanced from Antioch to the Black Sea (A.D. 1068-1071).

Alp Arslan fell by the hand of an assassin, A.D. 1072, and was succeeded by his son Malek Shah, who reigned prosperously twenty years. He was the first Turk who bore the title of "Commander of the Faithful." By his personal merit and the extent of his empire, he was the greatest prince of his age. From the Chinese frontier, he stretched his immediate jurisdiction or feudatory sway to the west and south as far as the mountains of Georgia, the neighborhood of Constantinople, the holy city of Jerusalem, and the spicy groves of Arabia Felix. This dominion surpassed the Asiatic reign of Cyrus and the Caliphs. His hunting train consisted of forty-seven thousand horses; a stud, surpassing that doubtless, of Nimrod, the "mighty hunter before the Lord."

But the greatness and union of the Seljukian angel-power expired in the person of Malek Shah, who died A.D. 1092. His vacant throne was disputed by his brother and his four sons. After a series of civil wars, the empire was divided into four dynasties -- the Persian, and those of Kerman, of Syria, and of Roum. The last invaded the Roman provinces of Asia Minor, A.D. 1074, under the lead of the valiant Soliman, who extended the bounds of the Seljukian kingdom of Roum to the Bosphorus and Hellespont; which, instead of "the great river Euphrates," became the eastern boundary of the Roman world.

"Since the first conquests of the caliphs," says Gibbon, "the establishment of the Turks in Anatolia was the most deplorable loss which the church and empire had sustained." Soliman’s new kingdom of the Romans, or Roum, is described as extending from the Euphrates to Constantinople, and from the Black Sea to the confines of Syria. Nice, the capital of Bithynia, was chosen for his fortress and palace; by which the throne of the Dynasty of Roum was planted one hundred miles from Constantinople. On the hard conditions of tribute and slavery, the Greek "worshippers of the daemonials and idols" might enjoy the exercise of their superstition; but their most holy temples were profaned; their priests and bishops were insulted; many thousands of their children were circumcised; and many thousand captives were devoted to the service, or the pleasures of their masters. A fleet of two hundred ships made Alexius, the Greek emperor, tremble behind the walls of his capital; and caused him to supplicate the compassion of the Latins in succor for the defence of the city of Constantine.