The Treaty of Edinburgh was negotiated by William Cecil.
All French forces were to be withdrawn to France. Their fortifications at Leith, Dunbar and Eyemouth were to be dismantled.
When William Cecil returned to England, he was far from being praised by Queen Elizabeth I.
He was met by a storm of complaints. Why had he not insisted that the negotiations include the return of Calais?
Suppose the Treaty of Edinburgh included the return of Calais to England. What happens then?