Virtus was a specific virtue in Ancient Rome. It carries connotations of valor, manliness, excellence, courage, character, and worth, perceived as masculine strengths (from Latin vir, "man"). It was thus a frequently stated virtue of Roman emperors, and was personified as a deity—Virtus.
The origins of the word virtus can be traced back to the Latin word vir, "man". The common list of attributes associated with virtus are typically perceived masculine strengths, which may indicate its derivation from vir. From the early to the later days of the Roman Empire, there appears to have been a development in how the concept was understood.
Originally virtus was used to describe specifically martial courage, but it eventually grew to be used to describe a range of Roman virtues. It was often divided into different qualities including prudentia (prudence), iustitia (justice), temperantia (temperance, self-control), and fortitudo (courage). This division of virtue as a whole into cardinal virtues is today classified as virtue ethics, as described by Plato's Republic and Aristotle's Nicomachean Ethics. It implies a link between virtus and the Greek concept of arete.
This inclusion leads to the belief that at one time virtus extended to cover a wide range of meanings that covered one general ethical ideal. The use of the word began to grow and shift to fit the new idea of what manliness meant. No longer did virtus mean that a person was a brave warrior but it could also mean that he was a good man, someone who did the right thing. During the time of the decline of the Roman elite virtus the Roman upper class no longer thought of themselves as unmanly if they did not serve in the military.