An Anglo-Scottish Treaty between King Edward IV of England and King James III of Scotland was agreed on 24 October 1474.
Reasons for an Anglo-Scottish Treaty in 1474
For the intended invasion of France to go ahead, England needed to make her peace with any who may intervene. This meant peace treaties with some nations and affirmations of trade deals, and mutual trust with others.
The most pressing of these deals was that with Scotland. If the bulk of the nobility and retainers were on campaign in France, the Scots could cause many problems through raids of an invasion of northern England. So, King Edward made terms with James III of Scotland.
“Forasmuch as this noble isle, called Great Britain, cannot be kept and maintained better in wealth and prosperity than that such things should be practiced and concluded between both the realms of Scotland and England, whereby they and their subjects might be encouraged to live in peace, love and tenderness, concluded that, considering the long continued troubles, dissensions and debates between the two realms, with great and mortal war that has followed therefrom, a nearer and more special way is to be found than merely the assurance of the present truce… The most convenient and direct road to this is to conclude a marriage between James, first born son and heir of James III and Cecily, youngest daughter of Edward IV… During the time of the truce neither shall favour or give assistance to traitors or rebels of the other…” Treaty of Edward IV and James III of Scotland, 24 October 1474.
The treaty was a success, lasting until 1482 when England invaded Scotland to intervene in matters pertaining to Scottish Kingship.
Encyclopedia.com. 1474 Treaty of Edinburgh (Several treaties listed, not chronologically)