The role THEN of the bishop of Rome in the first millenium , was still too much for the E Orthodox to accept towards the see of Peter…
Actually there was not a schism until the second millenium. There was not argument over the role of the successor of Peter in the first millenium. It was not until the Bishop of Rome attempted to force Latinizations onto the Eastern Christians, compelling them to reject what they had received from their apostles, that the “supremacy” issue became a problem.
I agree with you, though, the role of the Bishop of Rome was quite different up until the Reformation. Subsequently, when lands and assets of the Church were confiscated by various political figures, and the Church property was reduced to Vatican City (loss of the Papal States), the secular power that had been exercised over most of Europe since the Emperor moved the seat of the Roman Empire to Constantinople evaporated.
The EO have had their own difficulties interfacing with politicians and governments. They often had to placate secular rulers in order to maintain a presence.
The rebellion of the Reformation brought about some very direct statements about the role of the Papacy that, although held in the West, were likely an affront to Eastern ears.
“Moreover, that every human creature is to be subject to the Roman pontiff, we declare, we state, we define, and we pronounce to be entirely from the necessity of salvation (‘de necessitate salutis’).”
Pope Boniface VIII, Unam Sanctam, n. 9
“And since it arises from the necessity of salvation (‘de necessitate salutis’) that all the faithful of Christ are to be subject to the Roman Pontiff, just as we are taught by the testimony of the divine Scriptures and of the holy Fathers, and as is declared by the Constitution of Pope Boniface VIII of happy memory, which begins ‘Unam Sanctam,’ for the salvation of the souls of the same faithful, and by the supreme authority of the Roman pontiff and of this holy See, and by the unity and power of the Church, his spouse, the same Constitution, being approved by the sacred Council, we renew and approve.”
Pope Leo X, Fifth Lateran Council, Session 11, 19 December 1516.
“For it is revealed that subjection to the Roman Pontiff is from the necessity of salvation (‘de necessitate salutis’).”
Saint Thomas Aquinas, opusc. contra errores Graec. fol. 9.