You're thinking of Philip II, Philip I was the third Argead king of Macedon and reigned back in the Archaic Period. There's a number of previous threads on this subject. Here's one I wrote myself, though there are any others, although there are many others. But the short version is that Sparta...really wasn't worth the trouble anymore. The Corinthian War and Epaminondas' crushing successes had largely removed the relevance of the Lacedaemonian state. What purpose was there in actively wasting time to attack them, when they submitted to Macedonian hegemony tacitly? The Spartans could provide little to the League of Corinth, and their attempted revolt, instigated, funded, and mainly fought by Persians at Megalopolis was rather underwhelming--Alexander considered it laughable, even.