His reputation as an Oriental scholar spread rapidly. When La Fôret’s memorable embassy to the Sultan was being organized by Francis I., the king was recommended to entrust to Postel a literary mission, somewhat similar to that undertaken during the reign of Louis Philippe, at the instance of M. de Villemain, one of the objects of which was to collect Greek and Oriental MSS. It was on his return from this expedition, (in which he visited Constantinople, Greece, Asia Minor, and part of Syria,) that Postel met Teseo Ambrosio at Venice, and published what may be said to have been the first systematic attempt as yet made to bring together materials for the philosophical investigation of the science of language—being a collection of the alphabets of twelve languages, with a slight account of each among the number.[92] He was soon after appointed Professor of Mathematics, and also of Oriental Languages, in the College de France; but the wild and visionary character of his mind appears to have been quite unsuited to any settled pursuit. He had conceived the idea that he was divinely called to the mission of uniting all Christians into one community, the head of which he recognized in Francis I. of France, whom he maintained to be the lineal descendant of Sem, the eldest of the sons of Noah. Under the notion that this was his pre-ordained vocation, he refused to accompany La Fôret on a second mission to the East, although he was pressed to do so by the king himself, and a sum of four thousand crowns was placed at his disposal for the purchase of manuscripts. He offered himself, in preference, to the newly founded society of the Jesuits; but his unsuitableness for that state soon became so apparent, that St. Ignatius of Loyola, then superior of the society, refused to receive him. After many wanderings in France, Italy, and Germany, and an imprisonment in Venice, (where his fanaticism reached its greatest height,) he undertook a second expedition to the East, in 1549, whence he returned in 1551, with a large number of valuable MSS. obtained through the French ambassador, D’Aramont, but wilder and more visionary than ever. He resumed his lectures in the College des Lombards, now the property of the Irish College in Paris. The crowds who flocked to hear him were so great, that they were obliged to assemble in the court, where he addressed them from one of the windows. His subsequent career was a strange alternation of successes and embroilments. The Emperor Ferdinand invited him to Vienna, as Professor of Mathematics. While there, he assisted Widmandstadt in the preparation of his Syriac New Testament. He left Vienna, however, after a short residence, and betook himself to Italy, in 1554 or 1555. He was put into prison in Rome, but liberated in 1557. In 1562 he returned to Paris. The extravagancies of his conduct and his teaching led to his being placed under a kind of honourable surveillance, in 1564, in the monastery of St. Martin des Champs, near