Ever since the Seventh Century Rusticus and Eleutherius have been associated with St. Dionysius (or Denis). The veneration of St. Dionysius at Paris goes back to an earlier period. St. Gregory of Tours frequently mentions the Basilica of St. Denis built a the suggestion of St. Genevieve. The saint martyred at Paris is to be distinguished from the Areopagite converted by St. Paul, whose veneration has ever been famous among the Greeks, and from the pseudo-Dionysius, a Syrian of the Fifth or Sixth Century.
(Source: The New Roman Missal, Rev. F. X. Lasance)