This page lists the councils held by the whole church at various times during history. These are different from conferences in that they are typically convened by churches or denominations, usually to address theological issues.
410 - Persia - Synod of Isaac - a formative council for the Church of the East, also called the Nestorian Church. Among other things, elevated the catholicos of Seleucia-Ctesiphon to be supreme among the bishops of the East.
424 - Persia - Synod of Dadyeshu. Declared the Patriarch of Seleucia-Ctesiphon to be the equal of any patriarch of East or West and subject to none.
553 - Constantinople - Fifth Ecumenical Council. A synod of the Catholic Church called by Byzantine/Roman Emperor Justinian I to deal with the "three chapters" controversy.
664 - Whitby, Ireland - Synod of Whitby. A watershed moment in relations between the Catholic and Celtic church.