The Tsarigrad Road (Bulgarian: Цариградски път, Serbo-Croatian: Carigradski drum / Цариградски друм, from Tsarigrad “City of the Tsar”, an old Slavic name of Istanbul), also called the Road to Istanbul, Imperial Road, Moravian Road, or Great Road, was one of the most important roads in the Middle Ages on the Balkan Peninsula; it linked Belgrade with Istanbul. Its forerunner was the Roman Via Militaris, and prior to that, still older pre-antique traffic that took place along this route. Many passed in both directions along what was to be the Tsarigrad Road: units, groups, and military formations came to pillage and kill (the Huns), or to defend (the Roman legions), or to conquer new frontiers (the Ottoman invasions). The mission of the brothers Saints Cyril and Methodius to Great Moravia to Christianize the Slavs passed along the same road.