The Collaborative International Dictionary
Prochronism
Prochronism \Pro"chro*nism\, n. [Gr. ? preceding in time; ? before + ? time: cf. F. prochronisme.] The dating of an event before the time it happened; an antedating; -- opposed to metachronism.
Wiktionary
prochronism
n. An error in chronological order in which one is ascribed an earlier time.