justly

oikeutetusti, aiheellisesti

syystä In a just or fair manner; rightfully.
1890, Robert Franklin Pennell, History of Rome:

His valor, wisdom, and justice made him justly popular, but caused him to be regarded with suspicion at Rome.

But the city on the River Clyde can justly claim to have turned the tide.

It is a pleasant imagination to conceive a spirit iustly ballanced betweene two equall desires.