# Set theorem counter to be Roman

I wanted to make the counter for a theorem displayed as capital roman numerals (I, II, III), but none of these attempts worked

\newtheorem{test}[\Roman{counter}]{Theorem}
\newtheorem{test}[Roman]{Theorem}


Is there a way to do this?

• Welcome to TeX.SX! Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – cfr Dec 10 '14 at 1:34

\newtheorem{test}{Theorem}

Defining a new theorem environment test defines a new counter test. The optional argument, such as you used, says the ‘test’ environment shares the counter of another theorem-like environment.