We entered Berlin from the west, as it seemed to me, but then struck off in a southerly direction and were soon in the commercial quarter of the city, all but deserted at that hour, save for the trams.  Then I caught a glimpse of lamps reflected in water, and the next moment the car had stopped on a bridge over a canal or river.  My companion sprang out and hurried me to a small gate in an iron railing enclosing a vast edifice looming black in the night, while the car moved off into the darkness.

The gate was open.  Half a dozen yards from it was a small, slender tower with a pointed roof jutting out from the corner of the building.  In the tower was a door which yielded easily to my companion’s vigorous push as a clock somewhere within the building beat a double stroke—­half-past ten.

The door led into a little vestibule brilliantly lit with electric light.  There a man was waiting, a fine, upstanding bearded fellow in a kind of green hunting costume.

“So, Payer!” said the young Uhlan.  “Here is the gentleman.  I shall be at the west entrance afterwards.  You will bring him down yourself to the car.”

“Jawohl, Herr Graf!” answered the man in green, and the lieutenant vanished through the door into the night.

A terrifying, an incredible suspicion that had overwhelmed me directly I stepped out of the car now came surging through my brain.  That vast, black edifice, that slender tower at the corner—­did I not know them?

Mechanically, I followed the man in green.  My suspicions deepened with every step.  In a little, they became certainty.  Up a shallow and winding stair, along a long and broad corridor, hung with rich tapestries, the polished parquet glistening faintly in the dim light, through splendid suites of gilded apartments with old pictures and splendid furniture... here a lackey with powdered hair yawning on a landing, there a sentry in field-grey immobile before a door...I was in the Berlin Schloss.

The Castle seemed to sleep.  A hushed silence lay over all.  Everywhere lights were dim, staircases wound down into emptiness, corridors stretched away into dusky solitude.  Now and then an attendant in evening dress tiptoed past us or an officer vanished round a corner, noiselessly save for a faint clink of spurs.

Thus we traversed, as it seemed to me, miles of silence and of twilight, and all the time my blood hammered at my temples and my throat grew dry as I thought of the ordeal that stood before me.  To whom was I thus bidden, secretly, in the night?

We were in a broad and pleasant passage now, panelled in cheerful light brown oak with red hangings.  After the desolation of the State apartments, this comfortable corridor had at least the appearance of leading to the habitation of man.  A giant trooper in field-grey with a curious silver gorget suspended round his neck by a chain paced up and down the passage, his jackboots making no sound upon the soft, thick carpet with which the floor was covered.