I'm currently learning a piece that has the following chords in the chorus (one chord per bar):
Em7 A Bm7 F#m7
Am I correct in assuming this is a I-IV-V-ii progression in the key of E minor?
For starters, major chords are written in RN capitals, minors in lower case. But, in Em, F#m is not a diatonic chord. I'd say it's more likely in D major, which uses all four chords diatonically. If so, them the RN will be ii, V, vi, iii.