On August 9, 681, at the 16th session of the Sixth Ecumenical Council in Constantinople, Presbyter Constantine first mentioned the Bulgarian state as such.
The Sixth Ecumenical Council (or the Third Council of Constantinople) was held from November 7, 680 to September 16, 681. Convened by Emperor Constantine IV the Persecuted, the council made 102 important decisions, condemned the patriarchs Sergius I, Pyrrhus and Cyrus, as well as Pope Honorius I.
In his speech, Presbyter Constantine of Apamea mentioned that if they had listened to him when he wanted to speak (at the beginning of the council), “we would not have suffered what we suffered during the year, that is, what we suffered in the war with Bulgaria”.
This speech of Constantine is associated with the dating of the peace treaty between Bulgaria and Byzantium, which is an international recognition of Danube Bulgaria. Therefore, the beginning of Danube Bulgaria is counted from 681. Technically, however, this is a recognition of part of the previously recognized Great Bulgaria under Heraclius Kubrat.