Roger Pearse discusses Roman attitudes toward magic in this post from August 8, 2009. He begins,
There were three sets of Roman legislation relating to magic. There was an edict in the Twelve Tables (ca. 451 BC); the laws of Sulla (81 BC); and the legislation of Constantine and other Christian emperors (after 312 AD).
(Apologies to Mr. Pearse for having initially misspelled his name).