The Treaty of Deabolis () was an agreement made in 1108 between Bohemond I of Antioch and Byzantine Emperor Alexios I Komnenos, in the wake of the First Crusade. It is named after the Byzantine fortress of Deabolis (modern Devol, Albania). Although the treaty was not immediately enforced, it was intended to make the Principality of Antioch a vassal state of the Byzantine Empire.
At the beginning of the First Crusade, crusader armies assembled at Constantinople and promised to return any land they might conquer to the Byzantine Empire. However, Bohemond, the son of Alexios' former enemy Robert Guiscard, claimed Antioch for himself. Alexios did not recognize the legitimacy of the principality, and Bohemond went to Europe looking for reinforcements. He initiated open warfare against Alexios, laying siege to Dyrrhachium, but was soon forced to surrender and negotiate with Alexios at the imperial camp at Deabolis, where the Treaty was signed.
Under the terms of the Treaty, Bohemond agreed to become a vassal of the emperor and to defend the Empire whenever needed. He also accepted the appointment of a Greek patriarch. In return, he was given the titles of sebastos (noble) and doux (duke) of Antioch, and he was guaranteed the right to bequeath the County of Edessa to his heirs. After this treaty was signed, Bohemond retreated to Apulia and died there. His nephew, Tancred, who was his regent in Antioch, refused to accept the terms of the treaty. Antioch came temporarily under Byzantine sway in 1137, but it was not until 1158 that it truly became a Byzantine vassal.
The Treaty of Deabolis is viewed as a typical example of the Byzantine tendency to settle disputes through diplomacy rather than warfare, and was both a result of and a cause for the distrust between the Byzantines and their Western European neighbors.
Background
In 1097, the crusader armies assembled at Constantinople having traveled in groups eastward through Europe. The Byzantine Emperor Alexios I Komnenos, who had requested only some western knights to serve as mercenaries to help fight the Seljuk Turks, blockaded these armies in the city and would not permit them to leave, until their leaders swore oaths promising to restore any land formerly belonging to the empire they might conquer on the way to Jerusalem.Spinka, Latin Church of the Early Crusades, 113 The crusaders eventually swore these oaths, individually rather than as a group. In return, Alexios gave them guides and a military escort.Anna Komnene, The Alexiad, X, 261 The crusaders were however exasperated by Byzantine tactics, such as negotiating the surrender of Nicaea from the Seljuks while it was still under siege by the crusaders, who hoped to plunder it to help finance their journey.Runciman, The First Crusade, 98 The crusaders, feeling betrayed by Alexios, who was able to recover a number of important cities and islands, and in fact much of western Asia Minor, continued on their way without Byzantine aid. In 1098, when Antioch had been captured after a long siege and the crusaders were in turn themselves besieged in the city, Alexios marched out to meet them, but hearing from Stephen of Blois that the situation was hopeless, he returned to Constantinople.Runciman, The First Crusade, 182-3 The crusaders, who had unexpectedly withstood the siege, believed Alexios had abandoned them and considered the Byzantines completely untrustworthy.Runciman, The First Crusade, 183 Therefore, they regarded their oaths to have been invalidated.Anna Komnene, The Alexiad, XI, 291
By 1100, there were several crusader states, including the Principality of Antioch, founded by Bohemond I in 1098. It was argued that Antioch should be returned to the Byzantines, despite Alexios's supposed betrayals,Raymond of Aguilers (III, 67) reports that Raymond de St.-Gilles opposed Bohemond's retention of Antioch on the ground that "we swore to the Emperor upon the Cross of the Lord and the crown of thorns, and upon many other sacred objects, that we would not retain without his will any city or fortress of all that belonged to his Empire." Nevertheless, after the capture of Antioch, the oath of allegiance was in the end repudiated (Spinka, Latin Church of the Early Crusades, 113). but Bohemond claimed it for himself.M. Angold, The Byzantine Empire, 1025–1118, 251 Alexios, of course, disagreed; Antioch had an important port, was a trade hub with Asia and a stronghold of the Eastern Orthodox Church, and was the host of the important Eastern Orthodox patriarch of Antioch. It had only been captured from the empire a few decades ago, unlike Jerusalem, which was much farther away and had not been in Byzantine hands for centuries. Alexios therefore did not recognize the legitimacy of the Principality, believing it should be returned to the Empire according to the oaths Bohemond had sworn in 1097. He therefore set about trying to evict Bohemond from Antioch.
Bohemond then provoked more enmity from both Alexios and the Eastern Orthodox Church in 1100, when he appointed Bernard of Valence the Latin patriarch, and at the same time expelled the Greek patriarch, John the Oxite, who fled to Constantinople.John IV of Antioch initially stayed in Antioch after the crusaders captured his city, and presided over both Greek and Latin clergy. He later quarreled with Bohemond, fled to Constantinople and abdicated (T.M. Kolbaba, Byzantine Perceptions of Latin Religious "Errors", 126 ). Soon thereafter, Bohemond was captured by the Danishmends of Syria and was imprisoned for three years, during which the Antiochenes chose his nephew Tancred as regent.Runciman, The First Crusade, 232 After Bohemond was released, he was defeated by the Seljuks at the Battle of Harran in 1104; this defeat led to renewed pressure on Antioch from both the Seljuks and the Byzantines. Bohemond left Tancred in control of Antioch and returned to the West, touring Italy and France for reinforcements. He won the backing of Pope Paschal IIModern scholars argue that Bohemond's planned attack on Epirus was kept secret from the Pope, who thought that he intended to launch a campaign in the Levant (J.G. Rowe, Paschal II, 181; J. Holifield, Tancred and Bohemond, 17 ). and the support of the French King Philip I, whose daughter he married. It is unclear whether his expedition had qualified as a crusade.
Bohemond's Norman relatives in Sicily had been in conflict with the Byzantine Empire for over 30 years; his father Robert Guiscard was one of the Empire's most formidable enemies. While Bohemond was away, Alexios sent an army to reoccupy Antioch and the cities of Cilicia. In 1107, having organized a new army for his planned crusade against the Muslims in Syria, Bohemond instead initiated open warfare against Alexios, crossing the Adriatic to lay siege to Dyrrhachium, the westernmost city of the Empire.Anna Komnene, The Alexiad, XII, 317* M. Angold, The Byzantine Empire, 1025–1118, 251* Norwich, Byzantium:The Decline and Fall, 47 However, much like his father, Bohemond was unable to make any significant advances into the Empire's interior; Alexios avoided a pitched battle and Bohemond's siege failed, partly due to a plague among his army.Norwich, Byzantium:The Decline and Fall, 48 Bohemond soon found himself in an impossible position, isolated in front of Dyrrhachium: his escape by sea was cut off by the Venetians, and Paschal II withdrew his support.M. Angold, The Byzantine Empire, 1025–1118, 251* S. Runciman, The First Crusade, 232
Settlements
In September 1108, Alexios requested that Bohemond negotiate with him at the imperial camp at Diabolis (Devol). Bohemond had no choice but to accept, now that his disease-stricken army would no longer be able to defeat Alexios in battle. He admitted he had violated the oath sworn in 1097,Anna Komnene, The Alexiad, XIII, 348–349* Norwich, Byzantium:The Decline and Fall, 48 but refused to acknowledge that it had any bearing on the present circumstances, as Alexios, in Bohemond's eyes, had also violated the agreement by turning back from the siege of Antioch in 1098. Alexios agreed to consider the oaths of 1097 invalid.The only clause of Alexios and Bohemond's previous agreement that was not declared void was the latter's swearing "liege-homage" to Alexios (Anna Komnene, The Alexiad, XIII, 349). The specific terms of the treaty were negotiated by the general Nikephoros Bryennios, and were recorded by Anna Komnene:Anna Komnene, The Alexiad, XIII, 348–358
Bohemond agreed to become a vassal of the emperor, and also of Alexios' son and heir John;Anna Komnene, The Alexiad, XIII, 349–350* Norwich, Byzantium:The Decline and Fall, 48 He agreed to help defend the empire, wherever and whenever he was required to do so, and agreed to an annual payment of 200 talents in return for this service; He was given the title of sebastos (noble), as well as doux (duke) of Antioch; He was granted as imperial fiefs of Antioch and Aleppo. The latter was not under the control of either the Crusaders or the Byzantines, but it was understood that Bohemond should try to conquer it); He agreed to return Laodicea and other Cilician territories to Alexios; He agreed to let Alexios appoint a Greek patriarch "among the disciples of the great church of Constantinople". The restoration of the Greek patriarch marked the acceptance of submission to the empire, but posed canonical questions, which were difficult to resolve.J. Richard, The Crusades, c.1071 – c.1291, 131Anna Komnene, The Alexiad, XIII, 354–355* Norwich, Byzantium:The Decline and Fall, 48
The terms were negotiated according to Bohemond's western understanding, so that he saw himself as a feudal vassal of Alexios, a "liege man" (homo ligius or ) with all the obligations this implied, as customary in the West: he was obliged to provide military assistance to the Emperor, except in wars where he was involved, and to serve him against all his enemies, in Europe and in Asia.J. Richard, The Crusades, c.1071 – c.1291, 130
Anna Komnene described the proceedings with very repetitive details, with Bohemond frequently pointing out his own mistakes and praising the benevolence of Alexios and the Empire; the proceedings must have been rather humiliating for Bohemond. On the other hand, Anna's work was meant to praise her father, and the terms of the treaty she recorded may not be entirely accurate.
"I swear to thee, our most powerful and holy Emperor, the Lord Alexios Komnenos, and to thy fellow-Emperor, the much-desired Lord John Porphyrogenitos that I will observe all the conditions to which I have agreed and spoken by my mouth and will keep them inviolate for all time and the things that are for the good of your Empire I care for now and will for ever care for and I will never harbor even the slightest thought of hatred or treachery towards you ... and everything that is for the benefit and honor of the Roman rule that I will both think of and execute. Thus may I enjoy the help of God, and of the Cross and of the holy Gospels." Oath sworn by Bohemond, concluding the Treaty of Devol, as recorded by Anna KomneneAnna Komnene, The Alexiad, XIII, 357