The Maiden Tower stands beneath the Basilica Cistern, and is bound up with the Crown of Sargon, a potent thing associated with a faceless ghost; the tower is reckoned a place of no small consequence for the recovering of that relic. It was the Blue Rider, a figure of the races, who let fall that the Crown of Sargon might be come at below the Maiden Tower. The whereabouts of the tower were in turn shared with a friendly cat near Papa Mert’s, the company signalling thereby their intent to pursue the crown.
Within, the Maiden Tower proved to be no ordinary keep but a passage through the ages: a hall of paired chambers, each recreating a vanished civilisation — a Babylonian larder, the Sumerian tomb of Gilgamesh and Ishtar, the last fragment of the Library of Alexandria, a steppe camp, a Persian war-council, a grave of riddles, a Song-dynasty hall, and a prehistoric cave — each a trial of a different virtue, sparing those who met it with curiosity and restraint rather than force. At its summit, above the clouds atop a great ziggurat, the Crown of Sargon rested upon a crowned skeleton, guarded by a black dragon that the company's success in the trials had left stripped of its terror and much of its strength. They passed the trials, overcame the dragon, and claimed the crown.