Editors. "John Zápolya makes a treaty with Suleiman I". The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14395, accessed 25 April 2014.]
The dethroned king of Hungary, John Zápolya, whose crown has recently been taken by Ferdinand of Bohemia, makes a treaty with the Ottoman Sultan Suleiman I. In this agreement, he recognises the Sultan's suzerainty.