This is a great question, so let's get into this in more detail!

The question here is is essentially, "what did Philip II (father of Alexander) do to the Spartans, and how do we know that?"

A thread! 1/25

First off, our sources for the life of Philip II are really poor. Unlike the multiple biographies we have of his son Alexander III ('the Great'), we have no sustained biography of Philip II. Consequently, we're left to piece together his reign from disparate sources. 2/25

There's a strong tradition that Philip II just left the Spartans alone. That tradition comes from Plutarch, who preserves that classic Laconic reply where Philip threatens that if he enters Spartan territory he would destroy them and they respond 'If' (Plut. De Garr. 17). 3/25

Frustratingly, some modern scholars repeat that tradition uncritically (e.g.Borza, In the Shadow of Olympus (1990), 225; otherwise excellent book) and so it gets included in things like the wikipedia article with the Laconic phrase and nothing more: https://t.co/VyazqjrkZ0 4/25

But we actually have a fair bit of evidence that Philip did invade Sparta and that the end results were less than the Spartans might have hoped for! 5/25