Herotodus lists 300 Spartans at Thermopylae, and over 5000 Greeks. It is possible that there are two different numbers because they describe two very different

Herotodus lists 300 Spartans at Thermopylae, and over 5000 Greeks. It is possible that there are two different numbers because they describe two very different things. Spartan military excellence is likely exaggerated, but it is also likely that there was a significant time period where their soldiers were individually superior to other communities, primarily as a result of better nutrition. Nutrition in early Greek agricultural communities is notoriously awful, while the severe inequality of Spartan society allowed them to maintain a realtively well-fed warrior class. Individual quality doesn't scale, however, while raw quantity does. The Spartans were able to demonstrate excellence in results on a small scale, such as the conquest of Messina, but as quantity became a more important factor they simply couldn't compete even as they maintained some degree of individual excellence. There are many things to dislike about Spartan society from a modern standpoint (such as their brutally oppressed slave underclass), but it is important to remember that this is a feature of almost all early agricultural societies.