April 23, 1016 - Death of Aethelred II (the Unready), one of the last Anglo-Saxon kings of England. He was buried at St. Paul's Cathedral.
April 23, 1224 - Eleanor, daughter of King John, married William Marshal, 2nd Earl of Pembroke (eldest son of the famous William Marshal).
April 23, 1564 and 1616 - The birth of playwright William Shakespeare at Stratford-upon-Avon. He died on his 52nd birthday.
April 23, 1661 - Charles II was crowned King of England, completing the restoration of the monarchy.
April 23 is St. George's Day in England.