French classical scholar who, by his scholarship and judgment, acquired great contemporary influence.

Salmasius studied at Paris (1604–06), where he became a Calvinist, and at Heidelberg (1606–09), where he discovered the Palatine (Greek Anthology) manuscript of the Greek Anthology. In 1610 he became avocat of the Dijon parlement, but in 1629, as a Protestant, he was not allowed to succeed his father as conseiller. In the same year his monumental commentary on Solinus' Polyhistor was published. His erudition, especially in philology—he knew Hebrew, Arabic, Syriac, Persian, and Coptic, as well as Greek and Latin—led to invitations from several universities, and in 1631 he became professor at Leiden. There he remained, except for a year (1650–51) at the Swedish court.

During the English Civil Wars (1642–51) Salmasius was regarded as an ally by Presbyterians and Parliamentarians. At whose instigation he wrote Defensio Regia pro Carolo I (“Defense of the Reign of Charles I”), which was published anonymously in November 1649, is not clear, but it seems certain that Charles II paid for the printing. The work contains, in contradiction to Salmasius' earlier views, a defense of absolute monarchy and a condemnation of the Parliamentary government in England. This publication provoked a scathing reply entitled Pro Populo Anglicano Defensio (1651; A Defense of the People of England, 1692) from John Milton (Milton, John), then secretary for foreign languages to the Commonwealth.