Roman roads

[Blxz]

By the sounds of things you lack a 'government'.

This is a special building chain, first step is a blueish text with sword icon called 'Military Occupation'. Second step is a Level of government. Almost always the longer to build governments are better but the romans can be a tricky one with their reforms. Sometimes, in southern italy early on and in Gaul it can be worthwhile to build the cheaper, quicker governments for access to foreign units.

Quick recap, Expensive, 10 turn Level 1 government building will allow you to build your factional barracks up to top level and likely recruit the best units your faction has to offer. The cheaper and quicker to build ones offer fewer factional units and more regional units. level 4 governments will not allow you to leave a family member inside as a governor without public order issuses in a few turns.

EDIT: Also, better governments (slower building) will allow you to build more infrastructure. So A level 1 will allow you to build all roman infrastructure while a level 4 will allow only minimal infrastructure. Roads are infrastructure along with other buildings.