Roman emperor, born in Spain; his great deeds in arms won him a consulship in 91, and in 97 Nerva invited him to be his colleague and successor; a year later he became sole emperor, ruled the empire with wisdom and vigour, set right the finances, upheld an impartial justice, and set on foot various schemes of improvement; suppressed the Christians as politically dangerous, but with no fanatic extravagance; remained above all a warrior and true leader of the legions, and crowned his military fame by his successful conquest of Dacia, in commemoration of which he is said to have erected the famous Trajan Column, which still stands in Rome (56-117).