The profane law-givers of Rome were never tempted by interest or superstition to multiply the forbidden degrees: but they inflexibly condemned the marriage of sisters and brothers, hesitated whether first cousins should be touched by the same interdict; revered the parental character of aunts and uncles, and treated affinity and adoption as a just imitation of the ties of blood. According to the proud maxims of the republic, a legal marriage could only be contracted by free citizens; an honorable, at least an ingenuous birth, was required for the spouse of a senator: but the blood of kings could never mingle in legitimate nuptials with the blood of a Roman; and the name of Stranger degraded Cleopatra and Berenice to live the _concubines_ of Mark Antony and Titus. This appellation, indeed, so injurious to the majesty, cannot without indulgence be applied to the manners of these oriental queens. A concubine, in the strict sense of the civilian, was a woman of servile or plebeian extraction, the sole and faithful companion of a Roman citizen, who continued in a state of celibacy. Her modest station, below the honors of a wife, above the infamy of a prostitute, was acknowledged and approved by the laws: from the age of Augustus to the tenth century, the use of this secondary marriage prevailed both in the West and East; and the humble virtues of a concubine were often preferred to the pomp and insolence of a noble matron. In this connection the two Antonines, the best of princes and of men, enjoyed the comforts of domestic love; the example was imitated by many citizens impatient of celibacy, but regardful of their families. If at any time they desired to legitimate their natural children, the conversion was instantly performed by the celebration of their nuptials with a partner whose fruitfulness and fidelity they had already tried.[31] By this epithet of _natural_, the offspring of the concubine were distinguished from the spurious brood of adultery, prostitution, and incest, to whom Justinian reluctantly grants the necessary aliments of life; and these natural children alone were capable of succeeding to a sixth part of the inheritance of their reputed father. According to the rigor of law, bastards were entitled to the name and condition of their mother, from whom they might derive the character of a slave, a stranger, or a citizen. The outcasts of every family were adopted without reproach as the children of the State.