Salman Rushdie in The New Statesman:
As we honour the four hundredth anniversaries of the deaths of William Shakespeare and Miguel de Cervantes Saavedra, it may be worth noting that while it’s generally accepted that the two giants died on the same date, 23 April 1616, it actually wasn’t the same day. By 1616 Spain had moved on to using the Gregorian calendar, while England still used the Julian, and was 11 days behind. (England clung to the old Julian dating system until 1752, and when the change finally came, there were riots and, it’s said, mobs in the streets shouting, “Give us back our 11 days!”) Both the coincidence of the dates and the difference in the calendars would, one suspects, have delighted the playful, erudite sensibilities of the two fathers of modern literature.
We don’t know if they were aware of each other, but they had a good deal in common, beginning right there in the “don’t know” zone, because they are both men of mystery; there are missing years in the record and, even more tellingly, missing documents. Neither man left behind much personal material. Very little to nothing in the way of letters, work diaries, abandoned drafts; just the colossal, completed oeuvres. “The rest is silence.” Consequently, both men have been prey to the kind of idiot theories that seek to dispute their authorship.