From Persia much new information was supplied by Jean Chardin, Jean Tavernier, Charles Hamilton, Jean de Thevenot and Father Jude Krusinski, and by English traders on the Caspian.
2 The existence of the Mandaeans has been known since the middle 'of the 17th century, when the first Christian missionaries, Ignatius a Jesu and Angelus a Sancto, began to labour among them at Basra; further information was gathered at a somewhat later date by Pietro della Valle' and Jean de Thevenot 5 (1633-1667), and in the following century by Engelbrecht Kaempfer (1651-1716), Jean Chardin (1643-1713) and Carsten Niebuhr.
The first European travellers who speak of them without mentioning their name are Thevenot (1665) and Fryer (1673).
During his prolonged residences abroad he acquired a thorough knowledge of the Arabic, Turkish and Persian languages and literatures, which, on his final return to France, enabled him to render valuable assistance to Thevenot, the keeper of the royal library, and to Barthelemy d'Herbelot.
At Paris he met men of science and letters - Peter Guenellon, the well-known Amsterdam physician; Ole Romer, the Danish astronomer; Thoynard, the critic; Melchisedech Thevenot, the traveller; Henri Justel, the jurist; and Francois Bernier, the expositor of Gassendi.