The city of Alexandria, which was founded by Alexander the Great, about 322 B.C., was, at the date of our story, one of the most populous, wealthy, and intellectual cities in the world. Situated twelve miles west of the Canopic mouth of the Nile, its walls were washed on the south by the placid waters of Lake Mareotis, and on the north by the Mediterranean Sea; and it was the seat and center of a vast industry and an almost unequaled commerce. The streets were straight and parallel, and the city was divided into four quarters by two magnificent highways, each two hundred feet wide, crossing each other at right angles, and built up on each side with splendid houses, temples, and public buildings of every kind. A vast necropolis lay west of the city, on the east a mighty hippodrome. In the northeastern part was the Regis Judæorum, or Jewish quarter, wherein the Israelites abode, but their business extended not only through the great city, but throughout the world. The western part was called Rhacotis, the Egyptian quarter, and contained, besides its vast Libyan population and magnificent residences, the great temple of Serapis, and the sacred statue of the god that had been brought thither out of Pontus. But Bruchium, the royal or Greek quarter, was the most splendid portion of the city, containing the palace of the Ptolemies, on Lochias, a peninsula stretching eastwardly, the library and museum, the Cæsarium, or temple of the Cæsars, and the Dicasterium, or court of justice, and other buildings that bore witness to the knowledge of Dinocrates the architect, who rebuilt the temple of Diana at Ephesus. About a mile from the mainland was the little island of Pharos, on which was a light-house over four hundred feet in height, that was begun by Ptolemy Soter, 300 B.C., and finished by Philadelphus, his successor. An artificial mole called Hepta Stadium, nearly a mile in length, connected the island with the mainland, and between this mole and Lochias was the great harbor, while on the other side of it was a smaller harbor, called Eunostos (safe return), in which was an artificial basin known as Kibotos (the chest), which was filled from and connected with Lake Mareotis by a canal, another arm of which stretched eastward to the mouth of the Nile. Throughout this vast metropolis, in every quarter thereof, undistinguished by dress, nationality, language, or manners, of almost every race under heaven, engaged in every avocation except official business or military services, unknown except to their co-religionists, dwelt the countless members of the Christian Church, forming numerous communities, or congregations, that, without any public visible organization, were yet bound together by bonds of faith and love stronger than any Roman statutes, or any ties of nature, or any ligaments of interest or of ambition. Of course, in so vast a population, an aged man and a young girl would be as indistinguishable