I'm not that great a writer, so I will make this mostly a gameplay AAR. Hope it keeps you entertained!
4th of September, 1479. Pamplona
This is our realm. 
Surrounded by France, Castille, and Aragon, we are in a very vulnerable position. We can only support a mere 3 land regiments and 2 navies. We feel threatened by all our neighbours, and the only country we have very good relations with is the Papal State. Our King is no better than teenager. But we have a duty towards our people, and we will not dishonour it.

First, we need to expand our trade outside our borders; helped by our free trade policy, it shouldn't be too hard to increase our income. We send merchants to the northern town of Lubeck, the richest known trading centre.

We also sent diplomats to friendly nations, and we got good responses from all. The Castilians have allowed us to grant them Military Access (which will prevent them from declaring war on us), and we have allied with Naples, Brittany, and Venice. Our current mission is to build an army for our nation, which we will do as soon as we get the manpower. We decide to build a second transport ship.

Only a few days later, our foolish ally Brittany declared war on France, hoping that their exhaustion from the war with Austria would improve their position. We are men of our word, so we accept and enter the war. 
At the same time, Naples declares war on our only very good friend, the Pope.
We also enter this war, which puts us at war with our ally Brittany. 
We send our only regiment, led by our "King", to siege Roussillon and force a weakened French regiment to retreat.

Four months later, France accepts peace with Austria ceding them territory, and Naples accepts peace with the Papal State, relieving us of the burden of having to fight our Breton friends. 
At the same time, the French siege our province of Bearn, and only three weeks later forces led by Louis XI attack us in Roussillon with an army thrice the size of ours: needless to say, we were exterminated.

Moreover, our navy that was blockading Gascogne lost a battle with the French, from which we retreated witout losing any ships.

Nobody thought we could get out of this one, but a month later Brittany accepts peace with France giving them a mere 8 ducats: the Basques were saved.

Immediately after the war, we establish Royal Marriages with Castille, England, Naples, Brittany, and Portugal, further expanding our lineage.
We also managed to recruit a cavalry regiment, the first regiment of our new Navarran Army. Our Trade in Lubeck now provides over 65% of our income.
It's now January 1482, and we have managed to survive.