were measured distances throughout the Empire,—a marble group representing Constantine and Helena standing on either side of a gigantic cross, and a second statue of Helena upon a pedestal of porphyry. It was in this Augustæum, moreover, that was to stand for a thousand years the huge equestrian statue of Justinian, known through all the world and described by many a traveller before the capture of the city by the Turks, who broke it into a thousand pieces. [Illustration: ST. HELENA AND THE CROSS. BY CRANACH. LICHTENSTEIN GALLERY, VIENNA. ] To the west of the Augustæum lay the Forum of Constantine, elliptical in form and surrounded by noble colonnades, which terminated at either end in a spacious portico in the shape of a triumphal arch. In the centre, which, according to an old tradition, marked the very spot on which Constantine had pitched his camp when besieging Licinius, stood, and still stands, though in sadly mutilated and shattered guise, the Column of Constantine, which has long been known either as the Burnt Pillar, owing to the damage which it has suffered by fire, or as the Porphyry Pillar, because of the material of which it was composed. There were eight drums of porphyry in all, brought specially from Rome, each about ten feet in height, bound with wide bands of brass wrought into the shape of laurel wreaths. These rested upon a stylobate of white marble, some nineteen feet high, which in turn stood upon a stereobate of similar height composed of four spacious steps. Sacred relics were enclosed—or are said to have been enclosed—within this pediment, including things so precious as Mary Magdalene’s alabaster box, the crosses of the two thieves who had suffered with Christ upon Mount Calvary, the adze with which Noah had fashioned the Ark out of rough, primeval timber, and—in strange company—the very Palladium of ancient Rome, transported from the Capitol to an alien and a rival soil. At the foot of the column there was placed the following inscription: “O Christ, Ruler and Master of the world, to Thee have I now consecrated this obedient city and this sceptre and the power of Rome. Guard and deliver it from every harm.” [Illustration: COLUMN OF CONSTANTINE THE GREAT. FROM GROSVENOR’S “CONSTANTINOPLE.” ]