Aequitas (genitive aequitatis) is the Latin concept of justice, equality, conformity, symmetry, or fairness. It is the origin of the English word "equity". In ancient Rome, it could refer to either the legal concept of equity, or fairness between individuals.
Cicero defined aequitas as "tripartite": the first, he said, pertained to the gods above (ad superos deos) and is equivalent to pietas, religious obligation; the second, to the Manes, the underworld spirits or spirits of the dead, and was sanctitas, that which is sacred; and the third pertaining to human beings (homines) was iustitia, "justice".
During the Roman Empire, Aequitas as a divine personification was part of the religious propaganda of the emperor, under the name Aequitas Augusti, which also appeared on coins. She is depicted on coins holding a cornucopiae and a balance scale (libra), which was more often a symbol of "honest measure" to the Romans than of justice.
- Quentin Skinner, Visions of Politics (Cambridge University Press, 2002), p. 49 online. See also George Mousourakis, The Historical and Institutional Context of Roman Law (Ashgate, 2003), pp. 28, 32–35.
- Cicero, Topica 90, as cited by Jerzy Linderski, "Q. Scipio Imperator," in Imperium sine fine: T. Robert S. Broughton and the Roman Republic (Franz Steiner, 1996), p. 175.
- J. Rufus Fears, "The Cult of Virtues and Roman Imperial Ideology," Aufstieg und Niedergang der römischen Welt II.17.2 (1981), pp. 897–898, 900, 903–904.
- Linderski, "Q. Scipio Imperator," p. 175.