Short answers, pulled from the story.
Trajan was a Roman emperor who ruled from AD 98 to 117. The Roman Senate awarded him the title optimus princeps, meaning "the best ruler," an honor that appeared on coins from 105 onward and was granted to no other emperor officially. The title was tied primarily to his role as a benefactor, including his return of confiscated property and his expansion of welfare programs.
Trajan was born on the 18th of September AD 53 in Italica, a Roman colony in what is now the Andalusian province of Seville in southern Spain. His family, the Ulpii and the Traii, traced their roots to the town of Tuder (modern Todi) in Umbria, central Italy; linguistic and archaeological evidence confirms their Osco-Umbrian origins.
Trajan fought two wars against Dacia, in 101-102 and 105-106, ultimately conquering the kingdom and incorporating it as a Roman province. He defeated King Decebalus, who committed suicide when cornered by Roman cavalry. The wars brought vast quantities of gold and silver to Rome and were commemorated by Trajan's Column in Rome, completed in 113, and the Tropaeum Traiani cenotaph in Moesia, built in 102.
Trajan instructed Pliny the Younger, governor of Bithynia-Pontus, to prosecute Christians who admitted their faith and refused to recant, executing them for obstinacy. He forbade anonymous denunciations as contrary to justice. Those who cursed Christ or offered prayers to the gods or to Trajan's statue were to be released; Roman citizens faced trial in Rome rather than local punishment.
Under Trajan the Roman Empire reached its greatest territorial extent. He annexed Dacia (modern Romania), the Nabataean Kingdom (creating the province of Arabia Petraea in modern southern Jordan and northwest Saudi Arabia), and during his Parthian campaign temporarily held Armenia, Mesopotamia, and territories reaching the Persian Gulf, though those eastern gains were largely abandoned after his death in 117.
Trajan's Forum, designed by the architect Apollodorus of Damascus, was the largest forum in Rome. Construction began in AD 107 and it was dedicated on the 1st of January, 112. Financed largely from Dacian war loot, it included a triumphal arch entrance, a forum space approximately 120 meters long and 90 meters wide, a monumental basilica, libraries, and Trajan's Column.