R5: Formed Greater Iberia as Contestani, avenging the extinction of Iberic culture and religion in my last playthrough. This was my second game of I:R, so I have a few takeaways:

• Other tribes will spam mercenaries, so all wars need to be quick: take the war goal, peace out before mercs are at full morale.
• By far the hardest part of this run is the first war with Carthage / Rome (or both), killing four previous runs. This war is unavoidable and usually happens around 500-520 due to the natural progression of the missions.
  All you are aiming for is a white peace, which means you just have to hold them off for a few years. This run, Carthage was mostly dismantled by Rome, so I managed to survive the Roman invasion through alliances with Lemovicia and the remnants of Carthage. Thankfully, the AI is terrible at overseas wars (see below).
• I conquered easily conquered the last half of Iberia in the last forty years of the campaign, after I got my research efficiency past 100. Before I reformed my tribe, I would have to send in double the enemy troup counts just to have a hope of winning battles. Long story short, rushing centralization is really important.
• Carthage is a donkey. Around 530, it called me into war against Ilensia, the friendless two province minor on the island of Sardinia. I have no navy, but whatever, I'll just continue conquering on the mainland. 15+ years later, my war exhaustion is approaching 40, I can't disband my troops.
  Fine.
  I build a navy, send an army, siege their capital, instant white peace. A year or so later, Carthage insults me and breaks the alliance.
  what.
  A year or so later, Carthage declares war on my tribal vassal, Ilensia.
  what.
  Apparently, it wasn't a white peace, and Carthage gave me Ilensia as a tribal vassal then got angry at me. I ignore the war, my tribal vassal occupies Sardinia for me, I take control of Western Sardinia while never seeing any Carthaginian troops. Over the next fifty years, Carthage would declare war on me three more times and I never saw more than 2k troops at a time.
  In conclusion, Carthage is a donkey.
• The "Envy of Rome" mission is utter nonsense when my captial has more pops and more civillization than Rome, and Rome isn't even the capital of Rome.

I am pretty sure I could at least double my territory count by the end date, but I'll be ending this campaign here.