authors as fell into the hands of ecclesiastical copyists were not
unusually employed for transcribing the works of the Christian Fathers
or the lives of saints. In such cases the erasion was so clumsily
performed as often to leave distinct traces of the previous letters. The
possibility of recovering lost writings from these palimpsests was first
suggested by Montfaucon in the seventeenth century; but the earliest
successful experiment of the kind was made by Bruns, a German scholar,
in the latter part of the eighteenth, century. The most distinguished
laborer in this field has been Angelo Mai, who commenced his work in
1814 on manuscripts in the Ambrosian Library at Milan, of which he was
then custodian. Transferred to the Vatican Library at Rome, he
discovered there, in 1821, a considerable portion of Cicero's _De
Republica_, which had been obliterated, and replaced by Saint
Augustine's Commentary on the Psalms. This latter being removed by
appropriate chemical applications, large portions of the original
writing remained legible, and were promptly given to the public.

This treatise Cicero evidently considered, and not without reason, as
his master-work. It was written in the prime of his mental vigor, in the
fifty-fourth year of his age, after ample experience in the affairs of
State, and while he still hoped, more than he feared for the future of
Rome. His object was to discuss in detail the principles and forms of
civil government, to define the grounds of preference for a republic
like that of Rome in its best days, and to describe the duties and
responsibilities of a good citizen, whether in public office or in
private life. He regarded this treatise, in its ethics, as his own
directory in the government of his province of Cilicia, and as binding
him, by the law of self-consistency, to unswerving uprightness and
faithfulness, He refers to these six books on the Republic as so many
hostages [Footnote: _Praedibus_.] for his uncorrupt integrity and