In Ancient Rome, during the Roman Republic (c. 400 B.C. - 18 B.C.) the equestrian class was an middle-upper class that was not part of the patrician families. Just when this class arose exactly is unknown, but it is known that it was derived from merchants and well educated plebians of Rome. This class was achieved by, basically, the aforementioned people becoming wealthy, bribing their way into political offices they were ineligible to hold (due to the fact they were not patricians) and securing large estates in their name. This was initially done with the motive of giving plebians more say in the Senate, however this soon ended.

As time went by the equestrian class was no longer a class one could work themselves into, but rather a middle-upper class one was born into, much like the patricians. This is due to the fact that the wealth and large estates of the original equestrians was inherited by their children, so that the second generation equestrian had lived their entire (or most) of their life in the middle-upper class, rather than the lower class of the plebians. Thus, a rift was produced and the equestrian class became recognised by the patricians. Since then, the equestrian class has had virtually all the rights of the patrician - the right to serve in the higher offices of the Senate, the right to hold land and the right to command armies. Many of the most influential Romans, such as Gnaeus Pompeius Magnus, were born into the equestrian class.