His violent disposition now led him to quarrel with a country gentleman who had insulted his sister, and his semi-exile was changed by lettre de cachet into imprisonment in the Chateau d'If.
The affair ended by his escaping to Switzerland, where Sophie joined him; they then went to Holland, where he lived by hackwork for the booksellers; meanwhile Mirabeau had been condemned to death at Pontarlier for rapt et vol, and in May 1777 he was seized by the French police, and imprisoned by a lettre de cachet in the castle of Vincennes.
But in the 14th century the principle was introduced that the order should be written, and hence arose the lettre de cachet.
The lettre de cachet belonged to the class of lettres closes, as opposed to lettres patentes, which contained the expression of the legal and permanent will of the king, and had to be furnished with the seal of state affixed by the chancellor.
In the case of organized bodies lettres de cachet were issued for the purpose of enjoining members to assemble or to accomplish some definite act; the provincial estates were convoked in this manner, and it was by a lettre de cachet (called lettre de jussion) that the king ordered a parlement to register a law in the teeth of its own remonstrances.
