May 20 – History, Events, Births, Deaths, Holidays and Observances On This Day
May 20 in History 325 – The First Council of Nicaea is formally opened, starting the first ecumenical council of the Christian Church. 491 – Empress Ariadne marries Anastasius I. The widowed Augusta is able to choose her successor for the Byzantine throne, after Zeno (late emperor) dies of dysentery. 685 – The Battle of Dun Nechtain is…
