Oh, great Sphinx,

I believe you are referring to Memnon, the governor of Thrace (in place 334 BCE). Memnon took it upon himself to expand the borders of his territory in defiance of Antipatros' office in Macedon. Antipatros marched into Thrace, but he had to abandon his attack on Memnon, as the situation with Agis III in the Peloponnese warranted his full attention (with a limited army). However, it appears that Antipatros struck a deal with Memnon, whose relation to the Macedonian crown was not completely rebelious, as he later (327/6 BCE) did not refuse Alexander's call to march with a Thracian cavalry to India.