Joachim II, Elector of Brandenburg, and the Duke of Liegnitz sign a
treaty which plans for a mutual succession in case one or other of
them fails to provide an heir for their territories.
Citation:
Editors. "Elector of Brandenburg and Duke of Liegnitz agree to mutual succession".
The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14593, accessed 19 June 2013.]