Gustavus Selenius (1579-1666) was the author of Das Schach-oder Konig-Spiel (Chess or King-play), the earliest detailed account of living chess and the earliest German chess book, in 1616. Gustavus Selenius was the pseudonym for August (Augustus) the Younger, the duke of Brunswick-Luneberg-Dannenberg. He also wrote nine books on cryptography. His use of chess notation in 64 numbers made his chess books too hard to study. Between 1590 and 1610, he had 70 sorcerers and witches burned. Duke Charles of Brunswick (Karl von Braunschweig), who played Paul Morphy in 1858, was a descendent of August the Younger.