Frequent war campaigns were another way of replenishing the existing food supplies by looting those of others. But it was also a way of protecting their own produce from any foreign machinations. For as long as these campaigns lasted, farmers were at the same time soldiers. In Archaic Greece, especially after the prevalence of the new war method, the hoplite phalanx, the roles of the farmer and the hoplite were closely related.

In most of the Greek cities, the citizens themselves had to obtain their equipment, so that they could participate in war campaigns. Sparta was an exception to this, since the city itself offered weapons to its soldiers. Inevitably, only those who belonged to economically powerful classes constituted the members of the troops. Originally, aristocrats made up mainly the cavalry. But with the gradual prevalence of the hoplite phalanx and with Solon's reforms in Athens, the zeugitai class or diakosiomedimnoi formed thereafter the army's basis.

The two leading economic classes, the pentakosiomedimnoi and the hippeis (triakosiomedimnoi), continued to man the cavalry. But gradually, the corps of the hippeis began to lose the dominant place that it occupied in the army and the chief role that it played in war until then. Therefore, it was possible that some of the pentakosiomedimnoi and the hippeis chose or were forced to serve in the corps of the hoplites. On the other hand, economically weaker classes participated as skirmishers or simple oarsmen.