hum, Macedonians of the FYROM seem to speak a dialect of Bulgarian, while most of the population is commonly classified as being of Slavic origin, is this not right? If this questions offer no further problems, the solution could be the re-editation of the Great Bulgary of the VIII and IX centuries.
Later on in the XIX century, as Bulgary emancipated itself from the Ottomans, its territory included today's FYROM from the 1876-78 until 1912, when it lost it to the Serbs in the Balkan wars, as shown in the pictures below:
As to ancient Macedonia, did Alexanders Macedonia reached to the territory of the present-day FYROM?
and can someone provide some detailed information about percentage of Hellenic desdendants among today's Macedonian Slavs?