This module converts between roman numerals (I, II, III, IV, V) and arabic numerals (1, 2, 3, 4, 5).
I tried and it worked for small numbers and the common cases. Unfortunately it seems to fail for some unusual roman numerals which are in wikipedia:
my $r1910 = 'MDCCCCX';
print arabic ($r1910), "\n";
Also, when it fails, it just gives an "undefined value" - may be it should print an error?
It says that it is restricted to ASCII symbols - that may have been true in 1995 but perhaps this can be updated for 2012?
Also, the namespace as "Roman" and the global exporting of the functions are a bit questionable.
Anyway if, like me, you are too lazy to code this yourself, it works for the common cases. I also think this would make a useful standalone script and would suggest adding a command-line roman/arabic converter using the module.