There's a narrative about Lacedaemon and its rise and eventual fall due to the upper class being too dependant on perioikoi and helots, especially since it suffered from slave uprisings. But what happened to the population of the city and the city itself in the centuries following its decline and leading up to modern Sparti's founding in 1834?
There's some pretty good stuff on this in the FAQ - see this older thread. Basically, throughout the 4th and 3rd centuries BC there were several attempts to restore the power of Sparta, but these were repeatedly smashed by the Macedonians, the Achaian League and the Romans. Even the major reform programme of Agis and Kleomenes in the late 3rd century BC could not bring Sparta to the level where it could compete with Hellenistic kingdoms and rival leagues. After the Roman conquest of Greece (formally and finally in 86 BC), Sparta became an irrelevant little town in the Peloponnese, famous with tourists for their public displays of quaint customs that supposedly went back to the city-state's heyday. Over the centuries, it sank ever further into insignificance.