Chapter 1: From Castile to Spain, 1444-1523
1. European affairs
With France rivaling me on day 1, my initial plan cannot be executed. Instead, my allies are Portugal, Burgundy and Austria. Aragon and France forms an alliance, which prevents me from taking aggressive actions throughout this period. The strongest alliance web is necessary to discourage Aragonese aggression.
My first expansion lies in the vassalization of Navarra, which needs to be done within 2 years (maybe even less), before France gets there first.
Before I can annex Granada, Burgundy declares on Provence and calls me in. Provence is occupied by me, and Burgundy gives me one of the provinces in the peace deal. Later on, the Papal States is forced to release Avignon, which I manage to diplo-vassalize, giving me a fort in southern France.
The southern front is probably something you would expect: annexation of Granada, and capture of Tangiers and Melilla (for the trade power).
Otherwise, I find no opportunity to expand for the first 30 years. The worst thing during this period is Burgundy dragging me into 2 more pointless wars, got badly beaten in the second, and triggered the Burgundian inheritance event. Bohemia, being the Emperor with at least 8 provinces, got the Imperial partition, though the personal unions have broken free before the inheritance fires.
At almost the same time, the death of the 0-0-0 Enrique (as heir) triggers the Castilian civil war, in which in got the option to support the Aragonese faction to get a 5-4-3 heir with strong claim. I need to kill 4 15-25k stacks to end the civil war, which costs a lot of manpower.
A swing of fortune starts in 1473, when the first Anglo-French war begins. Now that France and Aragon are distracted, I can declare my own war against England.
The most difficult part of this war is to defeat the Royal Navy, which still has the largest number of heavy ships. However, after a long series of maneuvers, I managed to collaborate with the Portuguese fleet to sink a few heavies with a bit of French help. This allows me to land troops on England, and finally reach 70% warscore after 6 years of war.
It’s unfortunate that Labourd has been taken by France, but I still get a core to release Guyenne, which is the best tactic to carve out a part of France in the first conflict. Bit of England everywhere, so that I can claim wherever I wish.
This pattern is later repeated in the 1490s, when France once gain declared war on England, and I follow suit to reap my share of profit.
2. The Iberian Wedding
Frankly speaking, I would restart if it does not fire. The entire Aragon at virtually no cost makes a huge difference in the first century of the game. My hopes of getting the union rise high when Enrique IV succeeds to the throne (not the 0-0-0 one, but the one that spawns in the civil war) and got Juana as an heir.
As you can see in this screenshot, Juana eventually succeeds to the throne in 1509, and within that year Iberian Wedding fires:
Aragon still has Naples under union, so I get two unions by this event.
This has shifted the balance of power between France and me in my favour, and it is best to strike before France can find other allies to replace Aragon.
3. European affairs, continued
Having the right Casus Belli is essential for expansion in Europe. My OPM vassal Guyenne gives me a Reconquest Casus Belli, ideal for taking land from France without incurring massive AE.
This war is badly conducted. France surprised me by having significant higher morale than me despite Castile having +15% morale as tradition. Later on, I find out the answer: the combination of Elan and defensive idea give them 20% extra morale than my armies, while Portugal and Aragon suffers even more badly.
At one point, my warscore drops to as low as
-45% despite I took one of their forts and lost none of mine, due to the abysmal battle warscore and ticking warscore against me for failing to hold the war goal. However, the war of attrition eventually has an impact on France; their only ally Florence is peaced out, and they finally lost their first key battle in southern France with their 45k troops and a little luck on my side. Bohemia finally senses the weakness of France and joins the conflict, allowing me to sweep across France almost unhindered.
The war has dragged on for 11 years before I can finally reach a desirable settlement.
I could have stayed in the war for a bit longer, but Picardie is about to fall to the Bohemians, and that province is the most important one to take.
England is allied to Bohemia, and participates in the war with France. Bohemia failed to beat the 25k French stack on their own, and is too weak to honour their English alliance. Despite the drain of resources in the French war, England is now an easy target. A 19-month war is enough to completely occupy England, so that another slice can be annexed.
With 10 admin tech and full legitimacy, now I can enact the decision to inherit Aragon.
Spain is finally formed. To summarize the first 80 years in Europe, I have destroyed England, weakened France, and secured Aragon and Naples. I don’t really have a choice as the French-Aragonese alliance is threatening my flank until Iberian Wedding fires in 1509, but with Spain formed, I can have a lot more freedom in picking overseas targets.
4. Idea selection, and the overseas theatre
Exploration, Administrative and Influence are the first 3 idea groups that I have taken.
Admin and Influence gives bonuses to 2 critical limiters in expansion: coring cost and diplomatic annexation cost. The -25% coring cost is already in effect, while the annexation cost reduction still requires 2 more ideas to be unlocked.
Exploration synergies with the Castilian Idea of Inter Catera, which gives a bonus colonist. Starting from the 1470s, the colonization begins. I pursued 2 paths at the same time: the African route to reach India, and the American route to the Mexican and Incan states ripe for taking. By 1523, I have reached the Cape in Africa and formed the first colonial nation in the Caribbean Islands.
5. Summary, or TL;DR
Initially limited by the French-Aragonese alliance, early expansion options are curtailed. Still, being opportunist allows me to take part of Provence and much of England before the Iberian Wedding in 1509 shifts Aragon’s allegiance and allows me to beat France for the first time after an initially disastrous 11-year war. At the same time, colonization begins in the 1470s, and starts to gain momentum after 1510. Cape and Havana are the furthest extent of the colonial empire in 1523.
This is not an optimal start (late Iberian Wedding, Burgundian Inheritance not in my favour, the Middle East ignored, only 5 provinces converted), but at least my principle rivals (England, France and Aragon) are either gone or weakened, the rulers are decent (currently 6-5-2 Juana) and the colonial empire is about to take shape. If I can dismantle France and the Ottoman Empire efficiently enough there may still be time for the One Faith to be achieved.
Finally, there are maps and screenshots to provide more information about the bigger picture.