John Doukas Vatatzes, born in about 1192 in Didymoteicho, was probably^[1][2] 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.^[3] John Doukas Vatatzes had two older brothers. The eldest was Isaac Doukas Vatatzes (1188-1261), while his younger brother died young. Through his marriage to Eudokia Angelina he fathered Theodora Doukaina Vatatzaina, who later married Michael VIII Palaiologos. The middle brother's name is unknown, but his daughter married the protovestiarios Alexios Raoul.^[4][5]

A successful soldier from a military family, John had risen to the position of protovestiarites when he was chosen in about 1216 by Emperor Theodore I Laskaris as the second husband for his daughter Irene Laskarina, following the death of her first husband, Andronikos Palaiologos.^[6] As husband of Laskaris' firstborn, who had no son of his own, John may have been the de facto heir to the throne, however the question of succession was left open; Laskaris may have hoped his own marriage to Maria of Courtenay in 1219 would produce a male heir.^[6] As a result, when John III became emperor in December 1221,^[a] following Theodore I's death in November,^[9][10] he had to suppress opposition to his rule by Laskaris' brothers, Alexios and Isaac. The struggle ended with the Battle of Poimanenon in 1224, in which his opponents were defeated in spite of support from the Latin Empire of Constantinople. John III's victory led to territorial concessions by the Latin Empire in 1225, followed by John's incursion into Europe, where he seized Adrianople.^[11]

John III's possession of Adrianople was terminated by Theodore Komnenos Doukas of Epirus and Thessalonica, who drove the Nicaean garrison out of Adrianople and annexed much of Thrace in 1227. The elimination of Theodore by Ivan Asen II of Bulgaria in 1230 put an end to the danger posed by Thessalonica, and John III made an alliance with Bulgaria against the Latin Empire.^[12]

In 1235 this alliance resulted in the restoration of the Bulgarian patriarchate and the marriage between Elena of Bulgaria and Theodore II, respectively Ivan Asen II's daughter and John III's son. In that same year, the Bulgarians and Nicaeans campaigned against the Latin Empire, and in 1236 they attempted a siege of Constantinople.^[12] Subsequently, Ivan Asen II adopted an ambivalent policy, effectively becoming neutral, and leaving John III to his own devices.

John III Vatatzes was greatly interested in the collection and copying of manuscripts, and William of Rubruck reports that he owned a copy of the missing books from Ovid's Fasti.^[13] Rubruck was critical of the Hellenic traditions he encountered in the Empire of Nicaea, specifically the feast day for Saint Felicity favored by John Vatatzes, which Friedrich Risch suggests would have been the Felicitanalia, practiced by Sulla to venerate Felicitas in the 1st century with an emphasis on inverting social norms, extolling truth and beauty, reciting profane and satirical verse and wearing ornamented "cenatoria", or dinner robes during the day.^[14]

In spite of some reverses against the Latin Empire in 1240, John III was able to take advantage of Ivan Asen II's death in 1241 to impose his own suzerainty over Thessalonica (in 1242), and later to annex this city, as well as much of Bulgarian Thrace in 1246.^[15] By 1247 he had established an effective stranglehold on Constantinople. In the last years of his reign Nicaean authority extended far to the west, where John III attempted to contain the expansion of Epirus. Michael's allies Golem of Kruja and Theodore Petraliphas defected to John III in 1252.^[16][17] John III died in Nymphaion in 1254, and was buried in the monastery of Sosandra, which he had founded, in the region of Magnesia.^[18]

In an attempt to save the ailing Latin empire after the joint Nicaean-Bulgarian siege of Constantinople in 1236, pope Gregory IX called for a crusade against Nicaea and wrote to John III in 1237 informing him of the impending crusader army.^[19] In the face of Bulgarian neutrality, John III sought allies elswhere, turning to the Holy Roman Emperor Frederick II von Hohenstaufen.^[20] Frederick II was a hated enemy of the papacy, having already been excomunnicated by Gregory IX in 1227, and in a letter composed sometime before his second excommunication in 1239, Frederick II wrote to John III lamenting the power of the pope in the west and praising John III for the power of the Byzantine emperor over the clergy. ^[21]

Warm relations between the two Roman empires had already begun after the Sixth Crusade (1228-1229), undertook by Frederick II to lift his first excommunication, when Frederick II received a Nicaean embassy bringing gold coins, gold-embroidered silk and horses among other gifts.^[22] By 1238, the two emperors had conclued an alliance. Frederick II agreed to recognize John III as the legitimate Byzantine emperor, albeit with the title "Emperor of the Greeks" (Grecorum imperator / Γραικῶν βασιλεύς), in exchange for mutual aid. That same year, John III sent Nicaean troops to participate in the Siege of Brescia and Frederick II forestalled Gregory IX's crusade headed by the Latin emperor Baldwin II in north Italy, forcing the crusaders to eventually take the overland route to Constantinople in 1239.^[23]

In early 1240, John III's wife Irene Lascarina died, and later that year John III married Frederick II's 10 year old daughter Constance II of Hohenstaufen to cement their alliance, who took the Greek name Anna.^[24] Despite the lack of children from the marriage and John III's affair with his wife's lady-in-waiting, the alliance between the two emperors continued until Frederick II's death in 1250.

After Gregory IX's death in 1241, the new pope Innocent IV continued the policies of his predecessor, and attempted to wage war on both emperors. At the Council of Lyon in 1245, Frederick was deposed as emperor and excommunicated, for, among a multitude of other reasons, marrying his daughter to John III who was called by Innocent IV "that enemy of God and the church."^[25] In the east, the pope called for another crusade against John III and entered into negotiations with the Mongols to invade Nicaea, but both efforts were unsuccessful.^[26] In the west, Innocent IV was much more successful against Frederick II, defeating the imperial army at the Battle of Parma in 1248.^[27] John III continued to send troops, including archers and infantryman, and subsidies to Italy via Epirus between 1247 and 1250 to aid his father-in-law, who finally triumphed over the papacy in the Battle of Cingoli in August 1250, however Frederick died of dysentry in December the same year.^[28]

After Frederick II's death, diplomatic activitiy briefly continued between the two empires, with John III's son Theodore II Doukas Laskaris delivering a memorial speech in which he admired Frederick II's struggle against the hostility of the western aristocracy and clergy.^[29] Frederick's son and successor Conrad IV sent an embassy to Nicaea in 1253 in order to return Constance-Anna's exiled family back to Italy, but Conrad IV and John III's deaths in 1254 ensured that a possible continuation of the imperial alliance never ensued; after Conrad's IV death, the Holy Roman Empire and the Kingdom of Sicily were divided.^[30] Frederick's other son Manfred, the last Hohenstaufen king of Sicily, was to prove hostile to the Nicaean cause, invading Nicaea's Albanian coast in 1257 and allying with Michael II Komnenos Doukas against Nicaea in 1259, providing troops for the Battle of Pelagonia.^[31] After the Nicaean victory, Michael VIII Palaiologos attempted to marry the widowed Constance-Anna, who had remained at the Nicaean court during the reigns of her stepson and stepgrandson, in order to secure an alliance with Manfred. However, Constance-Anna refused and moved to her brother's court in Sicily in 1261, thus severing all ties with Byzantium and formally ending the alliance started by John III and Frederick II.^[32]

John III Doukas Vatatzes married first Irene Lascarina, the daughter of his predecessor Theodore I Laskaris in 1212.^[18] They had one son, the future Theodore II Doukas Laskaris. Irene fell from a horse and was so badly injured that she was unable to have any more children.

Irene retired to a convent, taking the monastic name Eugenia, and died there in summer of 1240.^[33] John III married as his second wife Constance II of Hohenstaufen,^[18] an illegitimate daughter of Emperor Frederick II by his mistress Bianca Lancia. They had no children.

John III Doukas Vatatzes was a successful ruler who laid the groundwork for Nicaea's recovery of Constantinople. He was successful in maintaining generally peaceful relations with his most powerful neighbors, Bulgaria and the Sultanate of Rum, and his network of diplomatic relations extended to the Holy Roman Empire and the Papacy. Among the armed forces he used were the large Cuman communities he had settled to guard Western Anatolia against invasions by Oghuz-Turkmens.^{[34][35][36][37][38]}

John III effected Nicaean expansion into Europe, where by the end of his reign he had annexed his former rival Thessalonica and had expanded at the expense of Bulgaria and Epirus. He also expanded Nicaean control over much of the Aegean and annexed the important island of Rhodes,^[39] while he supported initiatives to free Crete from Venetian occupation aiming toward its re-unification with the Byzantine empire of Nicaea.^[40]

Styling himself the true inheritor of the Roman Empire, John III encouraged justice and charity, and provided active leadership in both peace and war despite his epilepsy. He carefully developed the internal prosperity and commerce of his realm, which became known for bountiful harvest festivals reportedly drawing on traditions from the Felicitas feast days described in the missing 11th book of Ovid's Book of Days.^[41]

A half-century after his death, John III was canonized as a saint, under the name John Vatatzes the Merciful^[b] and is commemorated annually on 4 November.^[42][43] George Akropolites mentions that the people saw to the construction of a temple in his honour in Nymphaeum, and that his cult as a saint quickly spread to the people of western Asia Minor.^[44] On the same day, since 2010, the Vatatzeia festival is organized at Didymoteicho by the local metropolitan bishop.^[45] Alice Gardiner remarked on the persistence of John's cult among the Ionian Greeks as late as the early 20th century, and on the contrast she witnessed where "the clergy and people of Magnesia and the neighbourhood revere his memory every fourth of November. But those who ramble and play about his ruined palace seldom connect it even with his name."^[46]

His feast day is formally an Eastern Orthodox holiday, although it is not commemorated with any special liturgy; there are two known historical akolouthiai for him, including an 1874 copy of an older Magnesian menaion for the month of November, which shows that in the 15th and 16th century, he was venerated as "the holy glorious equal of the Apostles and emperor John Vatatzes, the new almsgiver in Magnesia."^[47] The relevant hymns are preserved in only one known manuscript in the library of the Leimonos monastery on Lesbos, Greece, and include references to the feast day for the almsgiver John Vatatzes.^[48] John III Vatatzes' feast day has largely fallen out of favor other than in the church dedicated to him in his birth city of Didymoteicho.^[49]

The generations after John Vatatzes looked back upon him as "the Father of the Greeks."^[50][c]

According to the legend, his incorrupt relics were transferred to Constantinople, which had been liberated from the Franks, where the legend of the reposed King became associated with him. At the time of the fall of Constantinople to the Ottoman Turks, his relics were hidden in a catacomb, and were guarded by a family of Crypto-Christians, which kept them secret from generation to generation. The legend states that since that time, he has been awaiting the liberation of Constantinople.^[52]

• List of Byzantine emperors

• Chisholm, Hugh, ed. (1911). "John III (Roman emperor)" . Encyclopædia Britannica. Vol. 15 (11th ed.). Cambridge University Press. p. 438.
• Kazhdan, Alexander, ed. (1991). The Oxford Dictionary of Byzantium. Oxford and New York: Oxford University Press. ISBN 0-19-504652-8.
• Fine, John V. A. Jr. (1994) [1987]. The Late Medieval Balkans: A Critical Survey from the Late Twelfth Century to the Ottoman Conquest. Ann Arbor, Michigan: University of Michigan Press. ISBN 0-472-08260-4.
• Jonathan Harris, Byzantium and the Crusades, London: Bloomsbury, 2nd ed., 2014. ISBN 978-1-78093-767-0
• John S. Langdon. Byzantium’s Last Imperial Offensive in Asia Minor: The Documentary Evidence for and Hagiographical Lore About John III Ducas Vatatzes' Crusade Against the Turks, 1222 or 1225 to 1231. New Rochelle, N.Y.: A.D. Caratzas, 1992.
• Macrides, Ruth (2007). George Akropolites: The History – Introduction, Translation and Commentary. Oxford: Oxford University Press. ISBN 978-0-19-921067-1.
• George Ostrogorsky. History of the Byzantine State. New Brunswick, N.J: Rutgers University Press, 1969.
• Polemis, Demetrios I. (1968). The Doukai: A Contribution to Byzantine Prosopography. London: The Athlone Press.
• Treadgold, Warren (1997). A History of the Byzantine State and Society. Stanford, California: Stanford University Press. ISBN 0-8047-2630-2.
• Varzos, Konstantinos (1984). Η Γενεαλογία των Κομνηνών [The Genealogy of the Komnenoi] (PDF) (in Greek). Vol. B. Thessaloniki: Centre for Byzantine Studies, University of Thessaloniki. OCLC 834784665.

•   Media related to John III Doukas Vatatzes at Wikimedia Commons