Like Eugene, Vitalian tried to restore the connection with Constantinople by making friendly advances to the Eastern Emperor
Constans II (641-668) and to prepare the way for the settlement of the
Monothelite controversy. He sent letters (synodica) announcing his elevation to the emperor and to Patriarch Peter of Constantinople, who was inclined to Monothelitism. The emperor confirmed the privileges of the
Roman Church and sent to Rome a codex of the Gospels in a cover of gold richly ornamented with precious stones as a good-will gesture.
The Patriarch Peter also replied, although his answer was somewhat noncommittal as to Monothelitism, a belief he defended. In his letter, he gave the impression of being in accord with the pope, whose letter to Peter had expounded the Catholic Faith. Thus ecclesiastical intercourse between Rome and Constantinople was restored, but the mutual reserve over the dogmatic question of Monothelitism remained. Vitalian's name was entered on the
diptychs of the
Byzantine Church--the only name of a pope so entered between the reign of
Honorius I (d. 638) and the
Sixth Ecumenical Council of 680-81.
The inclusion of Vitalian's name on the diptych was seen as some as being too conciliatory towards heresy, but that charge was unfounded.
Vitalian showed reciprocity toward Constans, when the latter came to Rome in 633, spending twelve days there during a campaign against the
Lombards. On 5 July the pope and members of the Roman clergy, met the emperor at the sixth milestane and accompanied him to St. Peter's, where the emperor offered gifts. The following Sunday, Constans went in state to St. Peter's, offered a pallium wrought with gold, and was present during the
Mass celebrated by the pope. The emperor dined with the pope on the following Saturday, attended Mass again on Sunday at St. Peter's, and after Mass took leave of the pope. On his departure Constans stole a large number of bronze artworks, including the bronze tiles from the roof of the
Pantheon, which had been dedicated to Christian worship.
Constans then raided
Sicily, oppressed the population, and was assassinated at Syracuse in 668. Vitalian supported Constans' son
Constantine IV against a usurper and thus helped him attain the throne. As Constantine had no desire to maintain the Monothelite decree (typus) of his father, Pope Vitalian made use of this inclination to take a more decided stand against Monothelitism and to win the emperor over to orthodoxy. In this latter attempt, however, he did not succeed. The Monothelite patriarch Theodore of Constantinople removed Vitalian's name from the diptychs. It was not until the Sixth Ecumenical Council (681) that Monothelitism was suppressed, and Vitalian's name was replaced on the diptychs of the Byzantine Church.