[1] Ecclesius was one of the bishops who joined Pope John I in 525 when he was sent by Theodoric the Great to Constantinople to express opposition to the Byzantine emperor Justin I's edict against Arian Christianity.

[2] Upon his return to Ravenna, Ecclesius came into conflict with a group of local priests, who protested against the bishop to Pope Felix IV.

Felix instead rebuked the dissenting clergy and reaffirmed Ecclesius's authority in a letter preserved by the historian Andreas Agnellus.

[3] It was also after his return from the east that Ecclesius began construction of the famous Basilica of San Vitale with the support of Julian the Banker (Julius Argentarius).

He also began construction of the Church of Santa Maria Maggiore [it] around the same time.