On This Day: May 20th

King Mohnyin Thado formally ascends to the throne of Ava.

King Sancho IV of Castile creates the Estudio de Escuelas de Generales in Alcalá de Henares.

The Second Battle of Lincoln is fought near Lincoln, England, resulting in the defeat of Prince Louis of France by William Marshal, 1st Earl of Pembroke.

A major earthquake hits Syria, widely felt between Sicily and Iraq.

A Magyar raiding army defeats forces of the Muslim frontier state of Fraxinetum.

Christopher Lekapenos is crowned Byzantine co-emperor by his father, emperor Romanos I Lekapenos, on the feast of Whitsun.

While visiting the royal Mercian court at Sutton Walls with a view to marrying princess Ælfthryth, King Æthelberht II of East Anglia is taken captive and beheaded.

The Battle of Dun Nechtain is fought between a Pictish army under King Bridei III and the invading Northumbrians under King Ecgfrith, who are decisively defeated.

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.

The First Council of Nicaea is formally opened, starting the first ecumenical council of the Christian Church.