To make a pun, a lot of what we know about Sparta is a cautionary tale.
The most vivid details that are associated with Sparta (the children thrown in chams, most of the agoge or krypteia details, and of course the good old fox kit eating the innards...) are from the Life of Lycurgus, where the author itself admit candidly that no one can be certain about anything about Lycurgus.
Which does not prevent Plutarch to states that....
For there was a dreadful inequality in this regard, the city was heavily burdened with indigent and helpless people, and wealth was wholly concentrated in the hands of a few. Determined, therefore, to banish insolence and envy and crime and luxury, and those yet more deep-seated and afflictive diseases of the state, poverty and wealth, he persuaded his fellow-citizens to make one parcel of all their territory and divide it up anew, and to live with one another on a basis of entire uniformity and equality in the means of subsistence, seeking preëminence through virtue alone, assured that there was no other difference or inequality between man and man than that which was established by blame for base actions and praise for good ones.
Is Plutarch actually writing about Lycurgus ? Or is he writing about Agis, Cleomenes or the Gracchus brothers ?(1) (With the caveat that the conveniently legendary Lycurgus succeeded and they did not) The question is not trivial, because this passage is the introduction of the three paragraphs that are about the land ownersh
up in Sparta, the iron brooches used as money, Spartan disdain of the arts, the communal messes....each sentence therein amounting to a ''fact'' about Sparta.
(1)Plutarch not being known for subtlety, a few lines later, a sentence explictly links a ''good'' measure of Lycurgus to a ''bad'' measure of Agesilaus.