400 should be CD
90 should be XC
You should not have a run of four numerals the same. If, as it looks, this is not complying with the rules then it is going to be nearly impossible to get a correct interpretation.
It looks like my first try was wrong anyhow.
So, M=1000.
L=50 or I=1 ?
CCC=300
So could be; CCC-L=250 or CCC-I=299.Either one dosn't really work because of the following numerals.
or;- CCCC=400
So could be CCCC-L=350 or CCCC-I=399. Same problem as above.
Then if CCC=300 the following CL=150
Then we have the problem of the Xs, there should not be four in a row, three would be 30 but 40 should be XL
LX would be 60 so we could have LX+XXX=90 but that should read XC
If it was MCCCCLXXXX without the L/l after the M then it could be 1490 if you take the the run of four Cs=400 and the L=50 + 40[four Xs]=90. The l is in the wrong place to deduct from XXXX and leave 39 making 1439. Although it is not correctly done so?

The problem is the L/I after the M. I cannot bsee why it's there.