I don't recall anyone in the 1920s using the term 'Uncle Tom' as an epithet. But what's amazing is how fast it caught on (in the 1930s). Black scholars picked up (the term) and just started throwing it at each other. [Ernest Allen, quoted in Hamilton, Kendra, "The Strange Career of Uncle Tom," Black Issues in Higher Education, June 2002]
As a verb, attested from 1937.
As to Lord Chatham, the victories, conquests, extension of our empire within these last five years, will annihilate his fame of course, and he may be replaced by Starvation Dundas, whose pious policy suggested that the devil of rebellion could be expelled only by fasting, though that never drove him out of Scotland. [Horace Walpole, letter to the Rev. William Mason, April 25, 1781]
In sum, it seems likely that the story of Veronica is a delightful legend without any solid historical basis; that Veronica is a purely fictitious, not a historical character, and that the story was invented to explain the relic. It aroused great interest in the later Middle Ages in the general devotional context of increased concern with the humanity of Christ, especially the Holy Face, and the physical elements of his Passion. [David Hugh Farmer, "The Oxford Dictionary of Saints," 1978]
Hence vernicle (mid-14c.) "picture of the face of Christ," from O.Fr. veronicle, variant of veronique.