1170 On this day in history birth of isabelle of Hainaut, queen of France (d. 1190)
1185 King Afonso II of Portugal (d. 1223) was born on this day in history.
1464 On April - 23 birth of johanna van Valois, Queen of France
1464 Robert Fayrfax, composer was born on April - 23.
1484 Julius Caesar Scaliger, Italy, scholar (On the Subtlety of Things) was born on this day in history.
1500 On this day in history birth of alexander Alesius, [Aless/Alane], System theologist/physician
1500 On this day in history birth of alexander Ales, Scottish theologian (d. 1565)
1516 On this day in history birth of georg Fabricius, German poet, historian, and archaeologist (d. 1571)
0034 On April - 23 death of christ, crucified, according to Isaac Newton
0303 Death of George, knight/saint/patron of England, beheaded on this day in history.
0725 Death of Wihtred, King of Kent on April - 23.
0871 On April - 23 ethelred I, king of Wessex/brother of Alfred the Great, dies
0990 On April - 23 ekkehart II, [Palatinus], monk to St-Gallen/poet, dies
0997 Vojtech "Adalbert" of Prague, 2nd bishop of Prague/apostle, dies at 40 on April - 23.
1014 Brian Boru, king of Ireland, dies in battle at 87 on this day in history.
1016 On April - 23 aethelbred II "the Unready", king of England (979-1016), dies