Trajan (Marcus Ulpius Trajanus), a Roman emperor, born in Italica, near Seville, Spain, Sept. 18, A. D. 52, died in Selinus (afterward called Trajanopolis), Cilicia, in August, 117. He was the son of Trajanus, an officer in the imperial service, and early embraced the profession of arms. He served as a military' tribune in the wars of the East, before 86 was made praetor, and in 91 became consul along with M. Acilius Glabrio. Afterward he went to Spain, and was sent by Do-mitian to Germany to command the troops on the lower Rhine. When at the close of 97 Nerva adopted him and chose him as his successor, the selection met with general acquiescence, although no previous emperor had been born out of Italy. His title after his elevation to the imperial dignity was Imperator Caesar Nerva Trajanus Augustus. In January, 98, Trajan, who was then encamped at Cologne, succeeded to the throne; but for many months he did not go to Rome, being engaged in war on the frontiers of the Rhine and the Danube. He entered Rome amid the acclamations of the people, and soon received, for his efforts to ameliorate the condition of the poor and to improve the judicature, the title of Pater Patriaa, and the new designation of Optimus. In 100 the younger Pliny, who was his warm personal friend, pronounced his panegyric upon him.

In 101 Trajan crossed the Danube, defeated Decebalus, the Dacian monarch, took many of his strong posts and his capital Sar-mizegitusa, and, having compelled him to sue for peace, returned to Rome in triumph with the title of Dacicus. In 104 Decebalus broke his treaty, refused to comply with the emperor's demand that he should surrender himself, and when Trajan inarched against him first attempted to poison his enemy. The conquest of Dacia was now determined upon, and an immense bridge was built across the Danube, over which the Roman army passed into that country. This bridge was the largest work of the kind ever built by the ancients, and, according to Dion Cassius, consisted of 20 piers, 150 ft. high, 60 ft. wide, 170 ft. apart, and united by wooden arches; it was probably in the neighborhood of the modern town of Tchernetz in W. Wallachia. Decebalus was defeated at all points, and in despair killed himself (106); Dacia was reduced to the condition of a Roman province, and fortified posts were built and colonists settled in it (107). When the emperor returned to Rome, he exhibited to the people games which lasted 123 days, and in which 11,000 animals were killed and 10,000 gladiators fought.

In the following years he carried on a campaign against the Parthians and Armenians, and was engaged in numerous military expeditions, the history of which is almost altogether lost. In the spring of 115 he marched against the Parthians, having previously received the submission of Armenia and the princes of the neighboring countries. He crossed the Tigris on a bridge of boats, subdued the country beyond that river, and returned to Antioch the same year. In 116 he again marched to the Tigris, and sailed down that stream to the Persian gulf, but was recalled by a general uprising in the provinces which he had reduced. Arriving at Ctesiphon, he gave the Parthians a king whom they quickly expelled. After the siege of Atrae in Mesopotamia he fell sick, and, leaving his successor Hadrian in command in Syria, started for Italy, but died on the way. His ashes were carried to Rome in a golden urn, and placed under the column bearing his name, which he had erected in honor of his Dacian victories. - For many generations afterward Trajan's reign was looked upon as the most brilliant in the imperial annals. The Roman arms were carried further than ever before or after, and rarely suffered defeat.

Besides the conquests in Dacia and beyond the Euphrates, Arabia Petraea was made subject to the empire by A. Cornelius Palma, the governor of Syria. Nor were his works for the internal improvement of his dominions less important. He constructed an artificial harbor at Centum Cellae (now Civita Vecchia), built the port of Ancona, made several great roads in various parts of the empire, one of which was across the Pontine marshes, and erected magnificent bridges. He founded several libraries in Rome, one of which, called Ulpia Bibliotheca, was very celebrated; built a theatre in the Campus Martius, and also the Forum Trajanuin, his great work, in the centre of which was the column of Trajan, erected in 112. It has been alleged that he was intemperate and licentious. Many writers doubt the magnitude of the persecution of the Christians which is said to have taken place during his reign. His correspondence with the younger Pliny, governor of Bithynia and Pontus, concerning the treatment of Christians, displays an unusual consideration for justice and humanity. In his reply to Pliny he says : "You have adopted the right course, my friend, with regard to the Christians; for no universal rule, to be applied in all cases, can be fixed in this matter.

They should not be searched for; but when accused and convicted, they should be punished; yet if any one denies that he has been a Christian, and proves it by action, namely, by worshipping our gods, he is to be pardoned upon his repentance, even though suspicion may still cleave to him from his antecedents. But anonymous accusations must not be admitted in any criminal process; it sets a bad example and is contrary to our age".