The Union of Lyons.

        The popes of the second half of the thirteenth century, in their eastern policy wished no repetition of the Fourth Crusade, which had failed to solve the extremely important problem of the Greek schism, and merely had served to postpone the other important question of a crusade to the Holy Land. Now it seemed desirable to the popes to achieve a peaceful union with the Greeks, which would put an end to the old schism and give grounds to hope for the liberation of Jerusalem. The recapture of Constantinople by the Greeks in 1261 was a heavy blow to the pope. Papal appeals to save what the Latins had accomplished in the East were sent to many sovereigns. But the papal attitude depended upon affairs in Italy: the popes, for example, did not wish to act with the Hohenstaufen Manfred, whom they hated. Yet when Manfred’s power in southern Italy was destroyed by Charles of Anjou, though the latter had been invited by the pope, his aggressive policy against Byzantium found no favor with the papacy. The popes realized that the power of Charles, increased by the conquest of Byzantium, would be hardly less dangerous to the world position of the papacy than the Hohenstaufen sway in Byzantium. It is interesting to note that the first union at Lyons under Michael Palaeologus was achieved not under the pressure of the eastern Turkish danger, but under the menace of the aggressive policy of Charles of Anjou.

        Since the Comneni, the attitude of the eastern Emperor towards the union had greatly changed. Under the Comneni, especially in the epoch of Manuel, the emperor had sought for union not only under pressure of the external Turkish danger but also in the hope, already merely an illusion, that with the aid of the pope he might gain supreme power over the West, i.e. restore the former Roman Empire. This aspiration clashed with the similar aspiration of the popes to attain supreme temporal power over the West, so that no union took place. The first Palaeologus, in his negotiations for union, had much more modest pretensions. He had in mind not the expansion of the Byzantine Empire in the West, but its defense, with the help of the pope, against the West in the person of the powerful and menacing Charles of Anjou. The papal curia met his proposals favorably, realizing that the ecclesiastical submission of Byzantium to Rome would bring about a political submission also even if the Sicilian danger were averted. But the possibility of such an increase of the temporal power of the pope met with definite resistance from western European rulers. In his turn, on his way to the reconciliation with the Roman church, the eastern Emperor met with stubborn opposition among the Greek clergy who, in an overwhelming majority, remained faithful to Greek Orthodoxy. The historian Norden said that Pope Gregory X “influenced the King of Sicily with spiritual reasons, Palaeologus his prelates with political arguments.”[241]

        One of the prominent representatives of the Greek church, the future patriarch John Beccus (Veccus), “a wise man, master of eloquence and science,”[242] according to Gregoras, had been opposed to union and was therefore imprisoned. During his confinement he became a partisan of the union and an active supporter of the Emperor in his project of reconciliation with Rome, an event of great importance for Michael’s aim.

        The council was held in 1274 in the French city of Lyons. Michael sent a solemn embassy headed by the former patriarch Germanus and the historian George Acropolitas, the grand logothete and the Emperor’s friend. It was intended that Thomas Aquinas, the most famous representative of medieval Catholic scholarship, should take the leading part at the council on behalf of Rome, but he died on his way to Lyons. His place was taken by the no less brilliant Cardinal Bonaventura. A Mongol bishop also attended the council.[243] The author of the Vita of Saint Bonaventura, Petrus Galesinius (Pietro Galesino) in the sixteenth century, and some other writers of the fifteenth and sixteenth centuries asserted that at the invitation of the pope Emperor Michael Palaeologus himself went to Lyons to attend the council. But this error was caught and refuted by Leo Allatius in the seventeenth century.[244]

        The Union of Lyons was achieved on condition that the Emperor should recognize filioque, azyme (unleavened bread), and the supreme authority of the pope; to all these stipulations, in the name of Michael, George Acropolitas took oath.[245] Michael also expressed to the pope his readiness to support by troops, money, and provisions the proposed joint crusade for the liberation of the Holy Land, but he stipulated that peace be established with Charles of Anjou so that the Emperor, in diverting all his forces to the East, need not fear attack from the West.[246]

        Neither side was pleased with the results of the union. As was to be expected, Michael met with stubborn resistance among the great majority of the Greek clergy. An antiunion council against Michael Palaeologus and John Beccus was held in Thessaly.[247] Moreover, the idea of a crusade could not be agreeable to the Emperor, who was unable to forget the warning of the Fourth Crusade. There was the additional difficulty that Michael Palaeologus was on good terms with the sultan of Egypt, the sworn enemy of the Latins of Syria.

        From 1274 to 1280, five papal embassies came to Constantinople in order to confirm the union. But in 1281 the new pope, the Frenchman Martin IV, whom Charles of Anjou set upon the papal throne, broke the union and gave entire support to Charles’ aggressive plans against Byzantium. But Michael regarded himself as formally bound by the Union of Lyons to the day of his death.