### István Geleji Katona (Gelej, 1589? - Gyulafehérvár, 1649)
He was a Calvinist religious writer. He studied in Heidelberg at Gábor Bethlen's expense, then he became the Rector of the Gyulafehérvár College, Bethlen's tutor, and a Transylvanian bishop. Together with János Dajka Keseru he compiled a song collection entitled Old Gradual. His Latin and Hungarian preaching books (Praeconium evangelicum, The Secret of Crisis, the Secret of Secrets) are the significant milestones of the history of the genre and Calvinist belief. His basic work on Hungarian linguistics and language teaching was Magyar Grammatikátska [Little Hungarian Grammar] (Gyulafehérvár, 1645) UG