... was a joint endeavour by Scotland and France, to resist England's aggressive expansion policies. It became a commercial alliance as well as a military one – enabling the Scots to enjoy a steady supply of fine French wines.
One is bound to assume that it wasn't always known by this name, although no–one seems to know when the term was first used – or, indeed, what it was called until then.
According to Wikipedia the alliance has never been formally revoked, although some consider it to have ended in 1560 with the signing of the Treaty of Edinburgh – which set up a new Anglo–Scottish accord, while reaffirming the peace between England and France that had been established in 1559 by the Treaty of Cateau–Cambresis.
In addition, Historic UK notes that "The original alliance that granted dual citizenship in both [France and Scotland] was eventually revoked by the French government in 1903."
In 1942, however, Charles de Gaulle felt able to describe his country's alliance with Scotland as "the oldest in the world". And if indeed it is still in force, it predates the alliance between England and Portugal – which those of us who live south of the border, at least, claim to be the world's oldest – by 78 years.
© Haydn Thompson 2021