In the heart of Thrace some ten miles north of the Rhodope mountains, there is a valley which is named Harpessus, after the stream which runs down it. Through this valley lies the main road from the east to the west, and along the road, returning from an expedition against the Alani, there marched, upon the fifth day of the month of June in the year 210, a small but compact Roman army. It consisted of three legions--the Jovian, the Cappadocian, and the men of Hercules. Ten turmæ of Gallic cavalry led the van, whilst the rear was covered by a regiment of Batavian Horse Guards, the immediate attendants of the Emperor Septimius Severus, who had conducted the campaign in person. The peasants who lined the low hills which fringed the valley looked with indifference upon the long files of dusty, heavily-burdened infantry, but they broke into murmurs of delight at the gold-faced cuirasses and high brazen horse-hair helmets of the guardsmen, applauding their stalwart figures, their martial bearing, and the stately black chargers which they rode. A soldier might know that it was the little weary men with their short swords, their heavy pikes over their shoulders, and their square shields slung upon their backs, who were the real terror of the enemies of the Empire, but to the eyes of the wondering Thracians it was this troop of glittering Apollos who bore Rome's victory upon their banners, and upheld the throne of the purple-togaed prince who rode before them. Among the scattered groups of peasants who looked on from a respectful distance at this military pageant, there were two men who attracted much attention from those who stood immediately around them. The one was commonplace enough--a little grey-headed man, with uncouth dress and a frame which was bent and warped by a long life of arduous toil, goat-driving and wood-chopping, among the mountains. It was the appearance of his youthful companion which had drawn the amazed observation of the bystanders. In stature he was such a giant as is seen but once or twice in each generation of mankind. Eight feet and two inches was his measure from his sandalled sole to the topmost curls of his tangled hair. Yet for all his mighty stature there was nothing heavy or clumsy in the man. His huge shoulders bore no redundant flesh, and his figure was straight and hard and supple as a young pine tree. A frayed suit of brown leather clung close to his giant body, and a cloak of undressed sheep-skin was slung from his shoulder. His bold blue eyes, shock of yellow hair and fair skin showed that he was of Gothic or northern blood, and the amazed expression upon his broad frank face as he stared at the passing troops told of a simple and uneventful life in some back valley of the Macedonian mountains. "I fear your mother was right when she advised that we keep you at home," said the old man anxiously. "Tree-cutting and wood-carrying will seem but dull work after such a sight as this."