This article presents evolution and correlation of basic legal notions. Polysemy of the notion of justice (ius) is shown, including its concurrence with the notion of law (lex). Down to the Modern Age the notion ius was an expression of justness. As a freedom, and in addition a primary one with respect to law, ius is understood only starting from the 17th century. The start of differentiation of justice (law) and morals was made as early as in Aristotle’s writings. A minimum of morality becomes stable with secular law (jus) already in medieval philosophy.