> the standard has mandated Roman literals in formating

By the way, in case anyone is wondering what this is, it just means that you can use the FORMAT function to output Roman numbers.

  (format t "~@r" 4)
  ;; => IV

You can also do:

  (format t "~r" 4)
  ;; => four

and just interpolating the number would use "d":

  (format t "The number is: ~d" 4)
  ;; => The number is: 4