Moving from the monograph of Silvia Niccolai on the tradition of the regulae iuris (legal maxims), the author investigates the establishment of principles of law as a legal category in 1920s Italy and the contribution of Giambattista Vico to the relationships between law and politics. With regard to both aspects, an emphasis is made as to the different ways to conceive of law as a form of knowledge which is able to connect the individual judgment on justice and fairness with requirements and demands of civil goverment.