military art, for he is described as "planning battles in his marble halls." Possibly he wrote a book on the subject. In the field he seems to have had little or no capacity. The Dacian chief, Decebalus by name, enticed the Roman general to cross the Danube, turned on him when the opportunity came, and defeated him with the loss of at least one legion and its exile. We have absolutely no record of the battle. It came within the period of events covered by the histories of Tacitus, but the book which contained the narrative is lost. Even did we possess it, we should still be ignorant of one important detail, for Orosius, who had the narrative before him, tells us that Tacitus held it to be the part of a good citizen to conceal the losses suffered by the armies of Rome. The whole story is wrapped in obscurity. It is said that the defeat of Fuscus was retrieved in the next campaign by his successor Julianus. But again we have no details. There is even to be found the statement, whether well or ill-founded we cannot say, that the Dacians exacted from Rome an annual sum of money as the price of their forbearance. It was to Dacia then that Trajan turned his thoughts when he found himself seated on the imperial throne. Trajan had many reasons for undertaking the enterprise. It was much to his taste. He was a soldier, who had already distinguished himself in the field. And he had to justify his elevation to the throne. The Empire really rested on the swords of the soldiers, and no man who could not count on the respect of the army could feel himself safe. And there was also the cogent reason that it was easier to attack than to defend, that the barbarians, if left to themselves, would sooner or later invade the Empire, and that the wisest plan would be to assume the offensive. Trajan was busied with protecting the German frontier of the Empire when he received the news that he had been adopted by the aged Nerva. He spent a year, after receiving the tidings, in completing the preparation for its defence. Then he went to take up his new dignity. Home affairs settled, he started for the Danube. Of the campaigns which followed we know little in one way, and much in another. We know, from the sculptures on Trajan's Column, exactly what arms and armour, and what engines of war were used by the soldiers of Rome. But as to the strategy of the campaign, and its chief incidents, we are almost wholly in the dark. [Illustration: Trajan besieging a Dacian Fort.]