The level beams of the evening sun filled the Basilica of St. John in Laterano. There were pearl lights and lights of sapphire; falling radiances of emerald and blood-red; vague translucent greens, that seemed to tremble under spiral clouds of incense. Now the sun was sinking behind Mount Janiculum. The clouds at the zenith of the heavens were rose-hued, but it was growing dark in the valleys, and the great church began to take on sombre hues. It seemed to frown upon him, to warn him not to enter, an impression he was long afterwards to remember, as he strode through the high-vaulted corridors. He hesitated, till the sound of a distant chant reached his ear. With a sort of fascination he could not account for, he watched the advance of the slowly gathering gloom, as an increasing greyness stole into the chapels. Evening was about to take the veil of night. The light left the stained-glass windows and the church grew darker and darker. The altar steps lay now in purple shadows that were growing deeper and denser each moment. Shadowy forms seemed to be moving about in the sanctuaries. Soon a monk entered with a taper, lighting the lights before some remote shrines. Tristan could not distinguish his features, for the light was very dim. Yet it enabled him to see that there were a few belated worshippers in the church. After a time the great nave was deserted. As the lone monk passed quickly through a sphere of thin light, Tristan gave a start. It seemed a ghost in a cassock that had vanished in the sacristy. He told himself that the impression was absurd, but he could not throw it off. He had caught a momentary glimpse of a face that had no human likeness, and the way in which the cassock had flapped about the limbs of the fleeting form seemed to suggest that it clothed a frame that had lost its flesh. Superstitious fear began to creep over him. He felt that he must seek the open, escape the haunting incense-saturated pall, these dim sepulchral chapels. Such light as there was, save what emanated from the candles on the altar, came from a stone lamp which cast its glimmer on the vanishing form. In every corner of the vast nave now lay fast gathering darkness. The figures of the saints seemed vague and formless. The altar loomed dim in the shadows. All these things Tristan noted. The whole interior of the church was now steeped in the dense pall of night, illumined only by the faint radiance of the lamp upon the altar, which seemed rather to intensify than to lift the gloom. A faint footfall was audible behind the carven screen, near the entrance to the chapels. A figure, almost lost in the gloom, glided into the nave, and shadows were falling about him like thin veils.