The first Lettice Knollys lived from 1543 to 1634. If this portrait dates to about 1615. the first Lettice would be about 72. This is either a second Lettice Knollys or Lettice’s youthful face from an earlier portrait placed in a ca. 1615 dress. With that insight, it turns out that this Lettice Knollys, according to her husband’s Wikipedia article, lived from 1583 to 1655. Her terse article in thepeerage is here.
From Lisby’s photostream on flickr.