Possible Clues:

• I, perhaps
• I, perhaps, mourn real man failing
• As such, I must be one
• Such as V, X or L
• Such a number is a letter
• One of the members of the XV maybe
• Normal manure should decompose, I say
• VII, for one (2 words)
• Plain upright sort with a figure for XIV perhaps
• Italian menu changed for oyster month by gangster is one of a kind in Eternal City