How can I write roman numbers in MathJax?

Question

I need to write roman numbers in MathJax. I've tried almost every way. But, then I decided to copy the symbol itself. But it looks very ugly.

For example,

$$\displaystyle \mathcal {D}^{{\left(II \right)}}_n $$

I tried LaTex syntax. \rom. But, unfortunately it doesn`t work.

Answer 1

Do you mean \mathrm{IX} perhaps? $\mathrm{IX}$?

There's a reason why the font family is called "Roman".