The Byzantine (Roman) Emperor Heraclius, after re-capturing Syria from the Sassanians, set up new defense lines from Gaza to the south end of the Dead Sea. These lines were only designed to protect communications from bandits, and the bulk of the Byzantine defenses were concentrated in Northern Syria facing the traditional foes, the Sassanid Persians. The drawback of this defense line was that it enabled the Muslims, advancing from the desert in the south, to reach as far north as Gaza before meeting regular Byzantine troops.