Gustavus II of Sweden lands in Pomerania and marches his army into
Germany, entering into the Thirty Years War for the first time in
hostility to Emperor Ferdinand II.
Citation:
Editors. "Gustavus II lands in Pomerania and marches his army into Germany".
The Literary Encyclopedia. First published 01 February 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=16008, accessed 19 May 2013.]