The Veiled Man by William le Queux

When my beard, now long, scraggy, and grey, was yet soft as silk upon my youthful chin, I was sent as spy into Agadez, the mysterious City of the Black Sultan. At that time it was the richest, most zealously guarded, and most strongly fortified town in the whole Sahara, and surrounded, as it constantly was, by marauding tribes and enemies of all sorts, a vigilant watch was kept day and night, and woe betide any stranger found within its colossal walls, for the most fiendish of tortures that the mind of man could devise was certain to be practised upon him, and his body eventually given to the hungry dogs at the city gate.

In order, however, to ascertain its true strength and the number of its garrison, I, as one of the younger and more adventurous of our clansmen, was chosen by Tamahu, our Sheikh, to enter and bring back report to our encampment in the rocky fastness of the Tignoutin. Therefore I removed my big black veil, assumed the white haik and burnouse of the Beni-Mansour, a peaceful tribe further north, and contrived to be captured as slave by a party of raiding Ennitra who were encamped by the well of Tafidet, five miles from the capital of Ahir. As I had anticipated, I was soon taken to the City of the Black Sultan, and there sold in the slave-market, first becoming the property of a Jew merchant, then of Hanaza, the Grand Vizier of the Sultan. As personal slave of this high official I was lodged within the palace, or Fada, that veritable city within a city, containing as it did nearly three thousand inhabitants, over one thousand of whom were inmates of his Majesty's harem.