The negotiations regarding the Trullan canons were conducted by the future Pope Gregory II. A degree of compromise (the "so-called Compromise of Nicomedia")—which "diplomatically skirted" the actual issue of their acceptance—was reached. While Constantine made concessions regarding the "economia", he did not give ground on the vast majority of the Roman grievances. The agreement was more designed to secure East-West political unity than resolve any doctrinal dispute. The fact of Constantine's having been summoned to Constantinople was the real proof that the "imperial writ still ran in Rome". Constantine left Constantinople in October 711. He was the last pope to visit the city until Paul VI did in 1967.