Spain and England, on the brink of war, sit down to discuss two major issues - establishing a border between English Georgia and Spanish Florida and the rights of commercial ships and privateers. Prime Minister Robert Walpole. The convention establishes a neutral ground between the two political entities from the Altamaha River to "San Juan," and calls for a board of commissioners to determine the exact location of the border. By the time the agreement is signed Oglethorpe had already built forts south of the mouth of the Altamaha, a fact Walpole would not have revealed.