In 1721, when he still had his seat on the fleurs-de-lis, he had published his _Lettres persanes,_ an imaginary trip of two exiled Parsees, freely criticising Paris and France.

The book appeared under the Regency, and bears the imprint of it in the licentiousness of the descriptions and the witty irreverence of the criticisms.

Sometimes, however, the future gravity of Montesquieu's genius reveals itself amidst the shrewd or biting judgments.

It is in the _Lettres persanes_ that he seeks to set up the notion of justice above the idea of God himself.

"Though there were no God," he says, "we should still be bound to love justice, that is to say, make every effort to be like that Being of whom we have so grand an idea, and who, if He existed, would of necessity be just." Holy Scripture, before Montesquieu, had affirmed more simply and more powerfully the unchangeable idea of justice in every soul of man.