The same year he visited Stockholm, where he made the acquaintance of Peter, son of Hugo Grotius, and in 1637 Hamburg, Upsala, Copenhagen, Leyden, and Amsterdam.
[3] Crossing to England in 1638, he fixed his quarters at Oxford, and corresponded with Archbishop James Ussher, who made him an allowance of £24 a year towards the expenses of a projected journey to the Levant in quest of manuscripts.
He left England in 1639, and, passing through Paris, was introduced by Grotius to Richelieu, whose offer of a post in the French diplomatic service he declined.
His book, A Generall Grammer for the Ebrew, Samaritan, Calde, Syriac, Arabic, and Ethiopic Tongue, was published in London in 1648.
Failing to obtain the chair of Arabic at Oxford, he accepted an offer of employment from Christina of Sweden, who appointed him professor of oriental languages at Upsala in 1650.