Editors. "Charles V agrees to a six-month truce with the Protestant princes". The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14618, accessed 20 June 2013.]
The Truce of Frankfurt is signed between Emperor Charles V and the Protestant princes of Germany. They demanded a permanent religious settlement, but Charles will commits himself to a six-month truce.