Re: Parthian Building Tree
Word of advice, don´t ever use the in-game building tree, it doesn´t work.
Can´t tell you how to solve your problem as I havn´t played Pahlava myself, but I know there´s been several thread about this, and I think there´s an answer to this in the FAQ or some other stickied thread as well, so search around a bit and see what you find.
Re: Parthian Building Tree
1 military occupation
2 migration
3 pastoralisme
4 large nomad market
5 settled communauty
6 warlord's horse herds
7 reformed pastoralism
8advanced settlement
9 settled aristocracy
10 reformed parthian government!
and it's only possible in "old" Persia and Mesopotamia...