Editors. "Schmalkaldic League holds a Diet at Frankfurt". The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14726, accessed 22 May 2013.]
The Diet of the Schmalkaldic League of Protestant princes convenes at Frankfurt, hostile to the Emperor Charles V, in a meeting that sits until February.