Brandenburg and Poland sign a treaty that arranges that succession
to the rule of Prussia will ultimately pass to the Elector of
Brandenburg.
Citation:
Editors. "Poland agrees to succession of the Elector of Brandenburg in Prussia".
The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=15023, accessed 24 May 2013.]