Pahlava Government?

[Cantu]

Hello! I think you have probably heard a lot about this, but I already searched the forums and still I'm left in the dark.

It is regarding Pahlava governments. I know that at start they behave like a nomadic faction, with pastoralism and nomadism government types, and the settlement + herds unit recruitment lines. This is until they get to a city which has been under heavy alexandrian influence (a list of these would be handy), there they can go "reformed pastoralism" and from there get the "reformed parthian government." It is between these two that I am stuck.

I built reformed pastoralism on my city, glad that I would finally get some serious units, then proceeded to build "advanced settlement," which quoting "caps off the settlement building line, meaning you will recruit from the barracks" or something like that. I expected to see my government building available after this, but to my surprise there is no government building AND my settlement line is dead.

I would really appreciate if someone would explain to me what I need to do now. At first I believed it had some other requirement (trade route was my first guess), but now searching the forums I'm not quite sure. It seems I need some "settled aristocracy" building from my settlement line (which I just killed with "advanced settlement", and was, if I remember, at large settled community level =( )

Please tell me I don't have to build it all over again :(

Thanks in advance.

EDIT: I'm guessing it's warlord's horse herds right