Request for variant subtag fr 16th-c 17th-c

[Michael Everson]

I am inclined to think that "16th-century" is not a very good subtag. 
What do we do when we have a language form that spans two centuries? 
Shall we register twenty of these for the Common Era, and ten or so 
for Before the Common Era? What about writing systems or languages 
that span millennia?

What would the meaning be for addig 16th-century to the language tag 
for Old English or Esperanto?
-- 
Michael Everson * http://www.evertype.com