The early societies of hunters and herders were often based on communism. But with the appearance of private wealth and the development of towns and cities inhabited by diverse people, some people emerged to 'guide' the rest. Gradually guides transformed into governors and governors into rulers. It's interesting to note how the meaning of words like Latin regere has changed over time.
Latin regere originally meant to guide or keep straight and later also took on the sense of lead or rule. It forms the base of English regime which is now used in sentences such as 'the new regime (government) is faced with many domestic and international challenges'. Similarly, regimen originally meant rule or government and later came to be used for 'prescribed or regulated procedure for physical or moral training, or promotion of health/stamina etc', as in, the army recruits follow a strict regimen or the doctor has prescribed him a daily regimen of walks and workouts.
Another related word is regiment which earlier carried the sense of management or control and by the early seventeenth century was being used to refer to an organised unit of the army, governed by a senior officer. It is sometimes also used as a verb to mean to systematize or organize (especially in strict order) or to discipline, as in, it was earlier believed that one of the primary functions of a school is to regiment children.
High Frequency Words for GRE, GMAT, SAT, CAT & Other Admission Tests:
Regime*, Regimen*, Regiment
The Peculiarity Of Peculation