The law of God, proclaimed not only in the Scriptures, but in the native instincts of the human soul, forbids intermarriages among those connected by close ties of consanguinity.  The necessity for such a law rests on considerations which can not here be fully explained.  They are considerations, however, which arise from causes inherent in the very nature of man as a social being, and which are of universal, perpetual, and insurmountable force.  To guard his creatures against the deplorable consequences, both physical and moral, which result from the practice of such marriages, the great Author of Nature has implanted in every mind an instinctive sense of their criminality, powerful enough to give effectual warning of the danger, and so universal as to cause a distinct condemnation of them to be recorded in almost every code of written law that has ever been promulgated among mankind.  The Persian sovereigns were, however, above all law, and every species of incestuous marriage was practiced by them without shame.  The Ptolemies followed their example.

One of the most striking exhibitions of the nature of incestuous domestic life which is afforded by the whole dismal panorama of pagan vice and crime, is presented in the history of the great-grandfather of the Cleopatra who is the principal subject of this narrative.  He was Ptolemy Physcon, the seventh in the line.  It is necessary to give some particulars of his history and that of his family, in order to explain the circumstances under which Cleopatra herself came upon the stage.  The name Physcon, which afterward became his historical designation, was originally given him in contempt and derision.  He was very small of stature in respect to height, but his gluttony and sensuality had made him immensely corpulent in body, so that he looked more like a monster than a man.  The term Physcon was a Greek word, which denoted opprobriously the ridiculous figure that he made.

The circumstances of Ptolemy Physcon’s accession to the throne afford not only a striking illustration of his character, but a very faithful though terrible picture of the manners and morals of the times.  He had been engaged in a long and cruel war with his brother, who was king before him, in which war he had perpetrated all imaginable atrocities, when at length his brother died, leaving as his survivors his wife, who was also his sister, and a son who was yet a child.  This son was properly the heir to the crown.  Physcon himself, being a brother, had no claim, as against a son.  The name of the queen was Cleopatra.  This was, in fact, a very common name among the princesses of the Ptolemaic line.  Cleopatra, besides her son, had a daughter, who was at this time a young and beautiful girl.  Her name was also Cleopatra.  She was, of course, the niece, as her mother was the sister, of Physcon.