Regional origins equestrian

Before the Middle Ages, most European armies were largely composed of infantry. Horsemen were used as advance scouts, raiding parties, troop escorts, and to outflank infantry lines. The majority of heavy fighting was done by infantry. Still, ancient armies required cavalry, and the horsemen usually belonged to the highest classes, as they were the only citizens able to afford horses. As a result, it was considered prestigious to own and ride a horse.
Ancient Rome was no exception to this rule, although the horsemen received financial compensation to buy a horse (the equus publicus, horse bought by the commonwealth). Thus, originally, the equestrians were a military as well as a political group. It is said that king Servius Tullius divided the Roman nation into centuries, which were not only units of soldiers on the battlefield but also voting units in the so-called Centuriate Assembly. The Roman historian Livy offers a description of a complex system with 18 centuries of cavalry, 170 centuries of infantry, and 2 centuries of engineers. When the centuries came together to vote, the equites centuries cast their 18 votes first, followed by the 172 remaining centuries, and one additional vote for those who were too poor to serve in the army but still had a political vote. (Although the fact that the people were divided belongs to the age of kings, it is likely that these specific numbers date back to the fourth century BC.)