I'm about 65 turns into my Makedonian campaign and I'm having a blast subjugating the Hellenic cities to the south prior to bringing the Epirotes "under my wing" and thrashing the barbarians to the North. Well, as I didn't realise until I got into a battle with the Epirotes that they had a (relatively) steady pool of elite units (the agema phalangites and royal peltasts and hypastites - ignore the spelling) whereas I did not. I said "meh" and believed that I hadn't acquired the correct military building to recruit such units of my own. I was wrong. Now that I am pretty far into my campaign, I've realised that I cannot recruit these units even after conquering over 15 provinces. Could someone please enlighten me on how to "unlock" these units for recruitment?