Heinsius was a native of Ghent. He studied at Leyden, where he was the favourite pupil, and, later, the successor of the celebrated Scaliger. He filled in succession the Chairs in the University, of Greek, of History, and of Political Science. Later, he was placed in charge of the library of the University, and served also as secretary of the Academic Senate. He was so far accepted as an authority on orthodox Calvinistic theology that he was selected to be the secretary of the Synod of Dort. He possessed the faculty, not very common with a man of scholarship, of writing and speaking gracefully not only in Latin, the literary language of the time, but also in his mother tongue. The young publisher, Louis Elzevir, while a man of ready intelligence and of rather varied attainments, had never had the leisure or the opportunity for scholarship. He may well, therefore, have considered himself fortunate in being able to secure at the outset of his ambitious publishing schemes the coöperation of a man like Heinsius, and it is not surprising that the influence of the professor became all-important in the direction of the publishing business. In many ways this relation was a fortunate one, but there were some offsetting considerations. The scholars of the time appear to have been not only a controversial but an irritable group, and Heinsius possessed the _genus irritabile_ to an exceptionable degree. He succeeded in embroiling the firm with a number of its scholarly friends and correspondents whose influence and whose coöperation it was important to retain. He was charged with having a special prejudice against, or hate of the German scholars, even of those who had associated themselves with Flemish or Dutch institutions. Among the men of note in the scholarly world who brought accusations against Heinsius for bad treatment and for malice, and who contended that the Elzevirs were seriously interfering with their relations with the scholarly world in retaining as their adviser so bad tempered, so unreasonable and so malicious a person, were Gebhardt, who held in the University of Groningen the Chair of Greek, Grotius the well-known publicist, Vossius, and, above all, Saumaise. The controversies between Saumaise and Heinsius, controversies carried on in part, so to speak, over the bodies of their publishers, continued over a series of years, and might well have formed the subject of a text in Disraeli’s _Amenities of Literature_. Saumaise, or Salmasius, was by birth a Frenchman, and his earlier university work was carried on in Paris. He then became intimate with Casaubon, through whose influence he became a Protestant. Later, he studied at Heidelberg, and the years between 1632 and 1650 he was associated with the University of Leyden. He then, at the instance of Queen Christina, passed some years in Sweden. Famous in various departments of learning, he was probably the chief authority of his time on philology. At the request of Charles II., at the time