Both Miguel Cervantes (author of The Ingenious Gentleman Don Quixote of La Mancha ) and William Shakespeare, two of the best-known writers in the world, died on 23 April 1616, 400 years ago
However, their death didn’t actually take place on the same day, because at that time Spain had already switched to the Gregorian calendar, while England still used the old Julian calendar. Shakespeare died on 23 April 1616 according to the old calendar, which is 3 May 1616 according to the calendar we use today. And Miguel Cervantes died on 22 April, in Madrid, but he was buried on 23 April 1616.
Anyway, even if neither Shakespeare nor Cervantes actually died on this date, it was accepted that they did and the correlation led UNESCO to declare this day the World Book and Copyright Day in 1995.