Dionysius_of_Halicarnassus, Roman Antiquities, trans. Cary, Loeb, 1935, 2, 19, 3 - 5. See also commentary in Roller, 1999, p.293 and note 39: "... one can see how a Phrygian [priest] in an elaborately embroidered robe might have clashed noticeably with the plain, largely monochromatic Roman tunic and toga"; cf Augustus's "efforts to stress the white toga as the proper dress for Romans."
