Sleidan, Or Sleidanns, Johann, a German author, whose real name was Philipson, born at Schleiden, near Cologne, in 1506, died in Stras-burg, Oct. 31, 1556. After studying in many universities, he was employed in diplomacy by King Francis I. of France. Having secretly adopted Lutheranism, he went to Strasburg, where in 1542 he was appointed by the Protestant princes historian of the Smalcald league, and by the town council professor of law. Subsequently he conducted negotiations with France and England, and attended the council of Trent as deputy from Strasburg, His reputation rests on his great work entitled De Statu Religionis et Reipvhlica', Carolo Quinto Ccesare, Commcntarii (1555; best ed., 3 vols., Frankfort, 1785-'6), in 25 books, to which a 26th was added from a manuscript found among his papers. It embraces a history of the reformation from 1517 to 1556, and is remarkable for impartiality and for its simple and elegant Latin. The best English version is that of E. Bohun, with a continuation to 1562, entitled " General History of the Reformation begun in Germany by M. Luther" (fob, London, 1689).