Editors. "New defensive Konigsberg league tries to gain French support". The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14809, accessed 19 April 2014.]
At Konigsberg, a new defensive league against Emperor Charles V is formed between Johann Albrecht of Mecklenburg, Albrecht Duke of Prussia and Hans of Custria. This allied group negotiates for an alliance with France.