answers: Constantine the Great
context: repaired, and was used continuously until the late 19th century. Walls of Constantinople The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul in Turkey) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from </s> threat emerged. In response, the sea walls were renovated in the early 8th century under Tiberios III (r. 698–705) or Anastasios II (r. 713–715). Michael II (r. 820–829) initiated a wide-scale reconstruction, eventually completed by his successor Theophilos (r. 829–842), which increased their height. As these repairs coincided with the capture of Crete by the Saracens, no expense was spared: As Constantine Manasses wrote, "the gold coins of the realm were spent as freely as worthless pebbles". Theophilos' extensive work, essentially rebuilding the sea walls, is testified to by the numerous inscriptions found or otherwise recorded that bear his name, </s> Aegean. Muhammad ibn Abdallah's fleet wintered at Smyrna, a fleet under a certain Qays (perhaps Abdallah ibn Qays) wintered in Lycia and Cilicia, and a third fleet, under Khalid, joined them later. According to the report of Theophanes, the Emperor Constantine IV (), upon learning of the Arab fleets' approach, began equipping his own fleet for war. Constantine's armament included siphon-bearing ships intended for the deployment of a newly developed incendiary substance, Greek fire. In 673, another Arab fleet, under Gunada ibn Abu Umayya, captured Tarsus in Cilicia, as well as Rhodes. The latter, midway between Syria and Constantinople, was
question: who constructed the massive defensive wall around constantinople in the early 5th century ce