Tomb of the last Macedonian King Perseus

To suggest that the inhabitants of FYROM are not Slavs is one of the most stupid things I have ever heard. Even a cursory look at their language will reveal a clear link with Bulgarian, meaning it is certainly a Slavic language.

As to the Ancient Macedonians, they were Greek. They spoke Greek, wrote in Greek, believed in Greek gods and took part in the Ancient Olympics. Ethnically and culturally they were Greeks, although certainly some of the strangest Greeks (eg. the structure of their state was quite distinct from the traditional Greek polis).

The modern Slavs living today in FYROM have neither cultural, ethnic nor linguistic link to the Ancient Macedonians.