Shakespeare and Cervantes died on the same date, but not on the same day.

Writers William Shakespeare and Miguel de Cervantes did not die on the same
day. While both writers died on April 23, 1616, it was when countries were
using two different calendar systems: the Gregorian and Julian calendars.
Cervantes died in Spain which used the Gregorian calendar, now referred to
as the Western calendar, and is widely used as of 2015. Shakespeare died in
England which still used the Julian calendar. England would not adopt the
Gregorian calendar until 1752. To switch from the Julian to Gregorian
calendar, countries had to add 10 days to the current date to get on track
with the new system. Therefore, if the switch to Gregorian was to occur
after July 6, the next day would be July 14. Shakespeare died 10 days after
Cervantes on May 3, 1616.