Typesetting Roman numerals within LaTeX text

Usually Roman numerals are used with counters for enumerated lists or as numbers for sectional units and the \roman and \Roman facilities do just this.

If all you want is to print some number in Roman numerals, here are two easy macros:

\newcommand{\upperRomannumeral}[1]{\uppercase\expandafter{\romannumeral#1}}
\newcommand{\lowerromannumeral}[1]{\romannumeral#1\relax}

Thus you can write

The king Louis~\upperRomannumeral{14} was called ``le roi soleil''

but typing Louis~XIV would be clearer and shorter.

If I understand you right, it seems like you are after in-line lists that are numbered in Roman numerals. I think the enumitem package is up to the job for this kind of thing.

Code

\documentclass[preview,border=5]{standalone}

\usepackage{enumitem}

\newlist{inlineroman}{enumerate*}{1}
\setlist[inlineroman]{itemjoin*={{, and }},afterlabel=~,label=\roman*.}

\newcommand{\inlinerom}[1]{
\begin{inlineroman}
#1
\end{inlineroman}
}

\newlist{Inlineroman}{enumerate*}{1}
\setlist[Inlineroman]{itemjoin*={{, and }},afterlabel=~,label=\Roman*.}

\newcommand{\InlineRom}[1]{
\begin{Inlineroman}
#1
\end{Inlineroman}
}

\begin{document}
I would like to cite some properties. Here are the properties listed in-line using small Roman numerals: \inlinerom{\item first, \item second \item third.}

Here are other properties listed as capital Roman numerals: \InlineRom{\item First property \item Second property \item Third property.}
\end{document}

Output

You might try using the biblatex package. It has a \RN command that does uppercase roman numerals. That way you don't have to create your own command. biblatex is usually loaded to do bibliographies, but it does the roman numerals as well.