His ecclesiastical career was immediately linked to his spiritual guide, Saint Abundius bishop of Como.

In summer 450 Senator, still a priest, was part of a deputation led by Abundius that took some letters of Pope Leo the Great to Constantinople.

[2] These letters, dated 17 June 450, were addressed to the Emperor Theodosius II, to the Empress Pulcheria and to the Patriarch of Constantinople Anatolius, and were issued to denounce their support to the doctrines of Eutyches, deemed to be heretic.

[3] In September 451 Abundius and Senator assisted to a local synod in Milan, attended by 18 bishops from all over northern Italy, where they gave an account of their journey to the East.

His feast day is celebrated in the Catholic Church on 28 May because 29 May was already occupied with another memory of saints.