The French and the Scots had a longstanding 'Auld Alliance' against
their common enemy. With the departure of the English army, headed
by their king Henry VIII, to France, James IV of Scotland seized
his opportunity to declare war on England.
Citation:
Editors. "James IV of Scotland declares war against England".
The Literary Encyclopedia. First published 01 November 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=14193, accessed 19 June 2013.]