The short answer to that, Nick, is yes and no. Confusingly (again) the Greek Dorian mode is the same as the mediaeval and modern Phrygian mode.

The mode is based on the Dorian tetrachord: descending, a series of falling intervals of two whole tones followed by a semitone. Applied to a whole octave, the Dorian mode was built upon two Dorian tetrachords separated by a whole tone, thus . . . [what I said before . . .]

Dick, you're giving me a headache and I haven't got anything here to play on. But C#F# is Phrygian (strictly speaking).