Having invaded Livonia, Charles XII of Sweden relieves Riga from
Russian occupation and subsequently invades Courland and Poland.
Citation:
Editors. "Charles XII of Sweden relieves Riga from Russian occupation".
The Literary Encyclopedia. First published 01 April 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=16995, accessed 23 May 2013.]