Our time span will be 108 years, starting with the Battle of Platea in 479 B.C. and ending with the Battle of Leuctra in 371 B.C. I chose Platea because it is a milestone victory for the Spartans – one where they were fully deployed, engaged, and victorious. The Spartans fielded 10,000 hoplites (5,000 Spartiates and 5,000 Periokoi) out of the allied total of 38,000. At Platea, the Spartans unquestionably showed their superior military skill.
Leuctra stands at the opposite end of the spectrum. Here the Spartans could only field 700 Spartiates, losing 400 of them during the battle. Leuctra was the end of the Spartan army as an effective fighting force.