“I can only pursue my instructions,” said Mr. Rawson dryly.  “They are, that the work be done in such a manner as to expose all concerned to a minimum of risk from these mysterious people; that if possible a Moslem be employed for the purpose; and that Mr. Cavanagh, here, shall always hold the key or keys to the case in the museum containing the slipper.  Will you undertake to look for some—­Eastern workmen, Mr. Bristol?  In the course of your inquiries you may possibly come across such a person.”

“I can try,” replied Bristol.  “Meanwhile, I take it, the safe must remain at Dulwich?”

“Certainly.  It should be guarded.”

“We are guarding it and shall guard it,” Bristol assured him.  “I only hope we catch someone trying to get at it!”

Shortly afterward Bristol and I left the office, and, his duties taking him to Scotland Yard, I returned to my chambers to survey the position in which I now found myself.  Indeed, it was a strange one enough, showing how great things have small beginnings; for, as a result of a steamer acquaintance I found myself involved in a dark business worthy of the Middle Ages.  That Professor Deeping should have stolen one of the holy slippers of Mohammed was no affair of mine, and that an awful being known as Hassan of Aleppo should have pursued it did not properly enter into my concerns; yet now, with a group of Eastern fanatics at large in England, I was become, in a sense, the custodian of the relic.  Moreover, I perceived that I had been chosen that I might safeguard myself.  What I knew of the matter might imperil me, but whilst I held the key to the reliquary, and held it fast, I might hope to remain immune though I must expect to be subjected to attempts.  It would be my affair to come to terms.

Contemplating these things I sat, in a world of dark dreams, unconscious of the comings and goings in the court below, unconscious of the hum which told of busy Fleet Street so near to me.  The weather, as is its uncomfortable habit in England, had suddenly grown tropically hot, plunging London into the vapours of an African spring, and the sun was streaming through my open window fully upon the table.

I mopped my clammy forehead, glancing with distaste at the pile of work which lay before me.  Then my eyes turned to an open quarto book.  It was the late Professor Deeping’s “Assyrian Mythology,” and embodied the result of his researches into the history of the Hashishin, the religious murderers of whose existence he had been so skeptical.  To the Chief of the Order, the terrible Sheikh Hassan of Aleppo, he referred as a “fabled being”; yet it was at the hands of this “fabled being” that he had met his end!  How incredible it all seemed.  But I knew full well how worthy of credence it was.

Then upon my gloomy musings a sound intruded—­the ringing of my door bell.  I rose from my chair with a weary sigh, went to the door, and opened it.  An aged Oriental stood without.  He was tall and straight, had a snow-white beard and clear-cut, handsome features.  He wore well-cut European garments and a green turban.  As I stood staring he saluted me gravely.