They date back only to the end of the 1920s. XIII the first relations of Frederick II both with the Byzantine successor states (the state of Epirus and the Empire of Nicea), and with the Frankish principalities (Latin Empire of Constantinople and the principality of Achaia) born from the disintegration of the Byzantine Empire in consequence of the IV crusade. The delay in making contact with the transionic states depended on the almost complete absence of subjects of the Kingdom of Sicilyin the conquest of Constantinople in 1204 and on the consequent partition of the former Byzantine Empire between the Republic of Venice. and the Crusaders at the time of the dynastic crisis of the Kingdom of Sicily, during the minority of the Swabian (1197-1208). Frederick II was thus forced to remain a passive spectator in the face of the foundation of a new Empire (precisely the Latin Empire) under a Western prince, while the traditional problem of the two Empires (the Byzantine and the Western) became that of five emperors’, since, besides Frederick II and the Latin emperor of Constantinople, also three other Greek sovereigns (namely the princes of Nicaea, Trebizond and Epirus- Thessalonica) used to call themselves emperors. In any case, in 1217 the Swabian obtained that the Latin emperor Peter of Courtenay was not crowned by Pope Honorius III either at the Vatican or at the Lateran, but only in S. Lorenzo fuori le Mura, to confirm the primacy of the Western emperor over the emperor of Constantinople.
The expansionist aims of Theodore Angelo Duca despot of Epirus, who in November 1224 had conquered the Latin Kingdom of Thessalonica and in 1226 had made himself acclaimed emperor, favored a contact between the sovereign of Epirus and the Swabian emperor. In fact, in the autumn of 1229 Theodore sent two embassies to Frederick II, the first of which was led by Maio Orsini, Count of Cefalonia, Zante and Ithaca and son-in-law of Teodoro Angelo, who had taken possession of the three Ionian islands following the IV crusade in 1206. Although Count Orsini was a native of Monopoli and therefore a subject of Frederick, he never paid homage to the emperor for the three islands, even when at the beginning of July 1228 Frederick stayed for two days in Kefalonia during the outward journey for the crusade in the Holy Land. Maio, on the other hand, had initially declared himself a vassal of Venice (1209), then of the prince of Achaia Goffredo di Villehardouin (1236). However, it seems likely that he was the architect of the first relations between the Swabian and the sovereign of Epirus. Unfortunately, the sources say nothing about the purpose of the Epirot embassy to Frederick II, but it is likely that Theodore asked for the support or at least the neutrality of the Swabian in view of a planned attack on Constantinople. And perhaps Frederick even sent some troops who on March 9, 1230 participated in the disastrous battle of Klokotnica against the Bulgarians, which ended with the capture of Theodore and the end of his dreams of greatness. On the other hand, the assertion (rightly rejected by Wellas, 1987) according to which Demetrius, Monferrato and king of Thessalonica (1207-1224), with his will, drawn up in Melfi in September 1230, would have transferred to the Swabian all his nominal rights over the Kingdom of Thessalonica. In fact, in his last will, Demetrius appointed Frederick II heir only to his own private assets.
The defeat of Klokotnica in any case resulted in the notable weakening of the state of Epirus-Thessalonica. In 1236 Michael managed to take possession of Epirus and the island of CorfuII Angelo, nephew of Theodore and Manuele Angelo, brother and successor of Theodore as emperor of Thessalonica and lord of Epirus. The usurper obviously feared the reaction of his uncle Manuele Angelo and, therefore, in all probability offered the Ionian island to Frederick II. In this context we must also read the letter with which in the spring of 1236 the Metropolitan of Corfu Giorgio Bardane replied to the Swabian emperor’s claim to obtain from Manuele Angelo also the formal handover of the island, a claim that was obviously rejected by the emperor of Thessalonica.. However, Frederick’s aims on Corfu remained frustrated, because, freed in 1237 from Bulgarian captivity, Teodoro Angelo first managed to depose his brother Manuele and then to reconquer the island, circumscribing for the moment to the Epirus the power of Michael II. In fact, even in the following years Michael II sought the support of Frederick II for his ambitions on the throne of Thessalonica and in the autumn of 1239 he sent his own emissaries to Puglia, mentioned several times in the famous fragment of Frederick’s register of the years 1239-1240, without however, the purpose of their embassy is known. Among the characters sent there was also the governor of Corfu Giovanni Comneno Vatatze (often mistakenly identified by historiography, as by Wellas, 1983, and recently also by Martin, 2002, with the homonymous emperor of Nicaea; but cf. the correction of Acconcia Longo, 1985-1986). mentioned several times in the famous fragment of Frederick’s register of the years 1239-1240, without however knowing the purpose of their embassy. Among the characters sent there was also the governor of Corfu Giovanni Comneno Vatatze (often mistakenly identified by historiography, as by Wellas, 1983, and recently also by Martin, 2002, with the homonymous emperor of Nicaea; but cf. the correction of Acconcia Longo, 1985-1986). mentioned several times in the famous fragment of Frederick’s register of the years 1239-1240, without however knowing the purpose of their embassy. Among the characters sent there was also the governor of Corfu Giovanni Comneno Vatatze (often mistakenly identified by historiography, as by Wellas, 1983, and recently also by Martin, 2002, with the homonymous emperor of Nicaea; but cf. the correction of Acconcia Longo, 1985-1986).