Certain dictionaries make a point of citing the earliest known written usage of a particular word. Sometimes, after the dictionary is published, someone tracks down an even earlier attestation of the word (which may end up getting cited in the next edition of the dictionary).
I seem to recall reading some article or discussion about the practice of looking for or chancing upon these "even-earlier-than-the-earliest-known" attestations, which can sometimes be a source of great excitement and friendly rivalry among lexicographers. I'm sure that there's a name for this—that is, for the practice of trying to find a usage that antedates the earliest usage recorded in a dictionary, or else for the earlier usages thereby discovered. Can anyone refresh my memory?