Roman Numerals in Major Click Here for Seventh Chords Theory Things   William Wieland
Major:IIVV(primary chords)
 diminished:viio(just one)
minor:iiiiivi(the rest)
  C: I ii iii IV V vi viiš I

Roman numerals in minorClick Here for More
minor:iivv(primary chords)
 diminished:iio(just one)
Major:IIIVIVII(the rest)
      UNLESS ACCIDENTALS
 e.g. leading tone: Vviio(like major)
  a: i iiš III iv v VI VII i
 
 
  a: V viiš