This can be reconciled by the nature of the Spartan army with an organisation based on year classes, with only the younger troops being mobilised for all but the gravest emergencies.
A mora was composed typically of hoplites, men armed with spears, swords and the heavy aspis shield and armoured in a cuirass, greaves and a helmet.
The unit was led by a Polemarch, the third (or arguably second) highest rank in Spartan hierarchy after the kings.
During the time of pure phalanx combat in Greece, the mora was a very difficult obstacle for an opposing commander to negotiate.
However, Iphicrates of Athens used a small, elite group of lightly armed peltasts to destroy one.