This weekend I finished the work on the unorganized bands migration event and made sure it worked correctly. From there, I started working on what would have been the tribal migration event. Though I decided to revise the design to simplify things quite a bit.

Instead of having a separate event for tribal migrations, I choose to use the same event I created for unorganized bands, except that now the event will try to pick either to migrate unorganized bands or to migrate tribal populations. The reasoning is that the basic structure for both migration event types is the same, so it would be wasteful and bad design to duplicate most of the code to create a new event only for tribal populations. Instead, the new event will shift its internal behavior according  to the type of population it's trying to migrate and use different migration target selection algorithms for each.

Aside from that, I modified the population split mechanic, which is the logic that extracts the population from a group to move into another. Now, when a population migrates out, the prominence for the associated polity or band will decrease on the original group, and the culture will also shift accordingly. Previously, beside losing population, a cell group remained political and culturally unchanged regardless of the amount of people that left. So polities would mostly grow and then remain static when they couldn't grow anymore. With this change it is now possible for a polity to lose prominence on a cell by just basically moving its population out. It will now also be possible for a polity to drive out unorganized bands and other polities that share the same cells, which will make it easier for territorial borders to shift around.

Next weekend I'll continue working on the migration algorithm. I hope to complete the new migration event that picks different populations to migrate without implementing the separate target selection logic  by then. After that, I'm going to work on separating the target selection logic for unorganized bands and tribal polities.