How to identify a roman numeral

Hello All, I am having trouble identifying a roman numeral. I need to separate the txt file by chapters so i use this pattern to do it, but it does not work.

Code :

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Pattern.compile("chapter [i+x*c*l*v*][i*x+c*l*v*][i*x*c+l*v*][i*x*c*l+v*][i*x*c*l*v+]")

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any ideas?

thanks alot

The link below has a good solution and explanation

regex - How do you match only valid roman numerals with a regular expression? - Stack Overflow