Saint Flavian (Greek - Φλαβιανος) was a very successful priest and was chosen to succeed Proclus as the Archbishop of Constantinople. During his consecration, Saint Flavian refused to give the Emperor Theodosius II a bribe and further angered the Emperor by refusing to make Theodosius's sister (Pulcherius) a deaconess. This refusal of a bribe created a situation in which the archimandrite Eutyches was supported by the Emperor against Saint Flavian.
In 448, the first council of Ephesus was called in an attempt to combat the growing Nestorian heresy that declared the human and divine natures of Christ are entirely separate. It was here that Eutyches argued that Christ had only one single nature, a type of monophyte doctrine. The council condemned this as heresy as well and set to excommunicate Eutyches. The eunich of the Emperor, Chrysaphius, who had tried to get Saint Flavian to pay his bribe during his consecration as Archbishop, was a personal friend of Eutyches and went to the Emperor to convince him of a second council to reconsider the doctrines of Eutyches.
This second council of Ephesus became known as the robber council was considered completely illegitimate and formally condemned afterwards. Saint Flavian, who had arrived at the council to maintain his doctrine and decisions was mortally beaten by a group of monks led by Barsumas and Eutyches. The council exiled him and declared Eutyches back in communion. Saint Flavian had been beaten so badly that he died three days later, still in exile at Hypaepa in Asian Minor on August 11, 449 AD.
Pope Leo I declared the second Council of Ephesus invalid and referred to the council as the "Robber Council". All decisions were declared void by the Pope. When Emperor Theodosius II died in 450 AD, the new Emperor Marcian had Saint Flavian's remains brought back to Constantinople. The Council of Chalcedon in 451 AD condemned Eutyches and declared Saint Flavian a martyr and Saint. Today his feast is celebrated on February 18th.