The Mongol invasion and the alliance against the Mongols.

        In the fourth and fifth decades of the thirteenth century there appeared from the East the menacing danger of the invasion of the Mongols, namely, the Tartars (in Byzantine sources, “Tahars, Tatars, Atars”). The hordes of Batu (Baty), one of the descendants of the famous Khan Temuchin, who had. assumed the title of Jenghiz Khan, i.e., “Grand Khan,” rushed into present-day European Russia and in their destructive and irresistible onslaught seized Kiev in 1240, then crossed the Carpathians, and arrived at Bohemia before they were forced to retrace their march to the Russian steppes. At the same time the other Mongol group, marching in a more southerly direction, conquered all Armenia with Erzerum and invaded Asia Minor, menacing the Sultanate of Rum or Iconium and the weak Empire of Trebizond. Under the pressure of common danger from the Mongols sprang the alliance of the three states of Asia Minor: the Sultanate of Iconium, the Empire of Nicaea, and the Empire of Trebizond, The Seljuqs and the military forces of Trebizond were defeated by the Mongols. After that, the Sultan of Iconium was compelled to relieve himself by paying tribute and supplying annually horses, hunting dogs, and the like. The Emperor of Trebizond, realizing the impossibility of fighting the Mongols, made a speedy peace with them and, on condition of paying an annual tribute, became a Mongol vassal. Fortunately for the Seljuqs and John Vatatzes, the Mongols occupied themselves with other military enterprises and temporarily suspended their onslaught upon the West, which enabled the Emperor of Nicaea to take decisive measures in the Balkan peninsula.

        From the example of the alliance mentioned above it is obvious that in the thirteenth century alliances between Christians and infidels did not trouble their participants; before the common danger the Orthodox emperors of Nicaea and Trebizond came to a friendly understanding with the Muhammedan Sultan of Iconium.

        In connection with the Tartar invasion two stories given by a western historian of the thirteenth century, Matthew of Paris, reflect some rumors circulating at that time in Europe.[85] In both, Matthew said that in 1248 two Mongol envoys were sent to the papal court and cordially received by Pope Innocent IV, who, like many other members of the Catholic church, hoped to convert the Mongols to Christianity. But in the first version he said also that at that time many supposed that the letter of the Mongol prince to the pope contained the proposition of the prince to make war against John Vatatzes (Battacium), “a Greek, son-in-law of Frederick, schismatic, and disobedient [son] of the papal curia; and this proposition was supposed not to be unpleasant to the Pope.” In his Historia Anglorum Matthew said that the pope directed the Mongol envoys to notify the king of the Tartars that, if the latter had adopted Christianity, he should march with all his troops upon John Vatatzes, “a Greek, son-in-law of Frederick, schismatic, and rebel against the pope and Emperor Baldwin, and after that upon Frederick himself who had risen against the Roman curia.” But the Tartar envoys, not liking to encourage “the mutual hatred of Christians,” answered through their interpreters, that they were not authorized to impose such conditions upon their master, and they feared that on receiving this news he would be very angry.

        Of course, neither of these versions, especially the second one, which reflects a kind of thirteenth century European gossip, has any real historical value,[86] and they cannot be treated as historical fact, as W. Miller regarded them. Referring to the second version, Miller wrote: “Having given the Holy Father this lesson in Christianity, the infidels returned to their own savage country.”[87] But it is very interesting to emphasize the fact that the political power and importance of John Vatatzes was widely and thoroughly appreciated and played a certain part, at least in the opinion of western European writers, in the negotiations between the pope and the Mongol envoys. The envoys were received with great esteem and attention by Innocent IV, who wrote to “their illustrious king, and to the nobles and to all the princes and barons of the Tartar army” a long letter, in which he urged them to adopt the Christian faith.[88] Of course, the name of John Vatatzes was not mentioned in this papal letter. Meanwhile John Vatatzes, relieved from the danger of Mongol invasion from the East, concentrated all his attention on the Balkan peninsula and obtained brilliant results.