 Some of these variants do not seem to have been used outside specific contexts, and may have been regarded as errors even by contemporaries.As Roman numerals are composed of ordinary alphabetic characters, there may sometimes be confusion with other uses of the same letters.For example, "XXX" and "XL" have other connotations in addition to their values as Roman numerals, while "IXL" more often than not is a gramogram of "I excel", and is in any case not an unambiguous Roman numeral.