A Russian force invades Livonia (a historic region along the
eastern coast of the Baltic, in present-day Latvia and Estonia).
This opens a war of succession to the Baltic lands of the German
knights which rages until 1571, and draws in conflicting claims to
the territories from Poland, Russia, Sweden and Denmark.
Citation:
Editors. "Russians invade Livonia in a war of succession".
The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14951, accessed 21 May 2013.]