I don't see why reinventing the wheel. ;-)
The datetime package supports several languages and, if one is not supported, the package author will surely be glad to add it. Perhaps also an interface for printing the year in Roman numerals would be useful in the package.
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[italian,english]{babel}
\usepackage{datetime}
\makeatletter
\newcommand\Romanyear{\@Roman{\year}}
\makeatother
\begin{document}
\monthname, \Romanyear
\selectlanguage{italian}
\monthname, \Romanyear
\end{document}

\MONTHand\YEARthat does that? – Werner Jun 18 '14 at 23:57\renew\yearand\month– Mario S. E. Jun 19 '14 at 00:01;-)– egreg Jun 19 '14 at 10:17;-)– egreg Jun 19 '14 at 10:37