John III Ducas Vatatzes

John III Ducas Vatatzes was the emperor of Nicaea from 1221 to 1254 and one of the most remarkable among the successors of Constantine the Great, being the chief architect of the restored Byzantine Empire, and a respected leader who encouraged justice, charity and a cultural blossoming from his capital at Nicaea (modern İznik, Turkey). He was the son of the general Basil Vatatzes, who was killed in battle in 1194, and his wife, a cousin of the Emperors Isaac II Angelos and Alexios III Angelos. He married Irene Laskarina, the daughter and heiress of Theodore I Laskaris, the founder of the Empire of Nicaea, and became his successor after his death in 1221. He had to face the opposition of some members of the Laskarid family, who claimed the throne, but he defeated them in the Battle of Poimanenon in 1224. He also had to deal with the threats of the Latin Empire of Constantinople, the rival Byzantine state of Epirus, and the Seljuk Turks. He made an alliance with Ivan Asen II of Bulgaria against the Latins and the Epirotes, and together they besieged Constantinople in 1235, but failed to capture it. He also expanded his territory in Asia Minor and the Aegean islands, and secured his borders with diplomatic and military actions. He reformed the administration, the army, the economy, and the church of his empire, and promoted education, arts, and sciences. He was a pious and benevolent ruler, who cared for the welfare of his subjects and supported many charitable institutions. He was also a patron of Orthodox monasticism and a defender of Orthodoxy against the Latin and the Muslim influences. He died in 1254 at Nymphaion (modern Kemalpaşa, Turkey), and was buried at the Monastery of Sosandra, near Magnesia. He was succeeded by his son Theodore II Laskaris, who continued his father's policies and achievements. He was later canonized by the Orthodox Church and is regarded as a saint and a national hero by the Greeks.