Philip of Macedon never took over Sparta. Do they stay independent forever? And the simple answer is no. In 333 BCE, Antipater defeats the Spartans at the Battle of Megalopolis and forces them into what we now call the League of Corinth. So let's keep now going back to where Alexander is. Antipater clearly was competent at maintaining power in Greece, and the next major battle that Alexander and his troops face is at Isis. And what makes Isis significant is that they are hugely outnumbered, historians disagree by how much they're outnumbered.