Editors. "Bavaria and Cologne intervene in the war on behalf of the Emperor". The Literary Encyclopedia. First published 01 April 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=16311, accessed 21 April 2014.]
In contravention of the Treaty of Ulm of March 1647, Maximilian of Bavaria and the Elector of Cologne move to support Holy Roman Emperor Ferdinand III, intervening in the Thirty Years War in his aid.