We don’t need to mark-up dates in Contributor bios. They function as strings of characters in the bios.

1700 would be a reasonable cut-off for other dates. After 1700, we’re into secondary sources, not primary sources. And whatever happened on a location after 1700 isn’t really “early modern” by the conventions of the discipline of English studies. (Early modern is more capacious for historians.)

The guiding principle needs to be: are we going to do anything with this date? Is it harvestable data, or information that we need to manage the site effectively? If not, then it’s just a string of characters.