After that fortuitous victory, a demeaning defeat was in order.
Catholic Ruthenia (a Kingdom level title) declared a Holy War against poor little Slavic Lesser Poland (a Duchy level title, one level below Kingdom).
Fortunately most of my neighbors to the West were still of the Slavic faith and joined my war. To the South was Orthodox Bulgaria, which was the local superpower. Somehow the various Kingdoms in Russia had become Catholic in this alternate timeline. The two County King of Poland had at some point become a Catholic; however he was also a member of my dynasty thanks to Poland at one point having an unmarried Queen willing to marry one of my relatives. This means he would not become involved in the war due to conflicting loyalties. This is unfortunate because it left me with only a few Duchy level allies to combat Ruthenia and other Catholic Russian forces.
I don't recall troop numbers, but with Slavic allies joining in the defense of the Slavic faith I was comfortable with my chances of victory. Even slightly distant Pruthenia (baltic coast Western Slavs) decided to join my war, with a sizable force, after my first battle.
I massed my army in my territory north of Ruthenia's siege, and waited until they attacked my army. The Slavic faith gives a substantial defensive bonus when on your own land, and the Polish special building gives light cavalry. Light cavalry isn't the greatest, but the building is called Hussar Training Ground or something along those lines and also gives +15% to Light cavalry's defense values which I assume is pretty nice in combination with defensive terrain and the Slavic bonus. I also had a Hussar retinue of 500 light cavalry at that point as well.
The result of the Ruthenian's attack seemed likely to be quite acceptable at first. Unfortunately before the battle had completed another few thousand Catholic troops joined the battle on the enemy side, skewing the numbers to a little better than 2:3. I had about 6000 allied Slavic troops to about 9000 Catholics.
Despite this, the Catholics suffered extremely heavy losses and I now had my Pruthenian allies' army untouched in Pruthenia. If I could consolidate our forces we would outnumber the Ruthenians. A Slavic Count joined the war on my side, and I retreated my forces in that direction in the hope the Pruthenians would start a march in my general direction. The Ruthenian Catholics settled in for a siege.
After a realm levy re-raise and merging of units, I went to meetup with the oddly stationary Count's army. The Count's army did not move until I was in the next County over after I marched several counties to his border, which I'm pretty sure is a bug as they should probably want to merge with my army rather than sit uselessly. I noted I had roughly the same number of troops as the Catholic army once the Count finally joined his forces to my army. I decided to assault the Catholic siege army in the hope of damaging it enough to slow it's siege, as the warscore was worryingly high after my initial loss.
To my disappointment, my army failed to perform nearly as well as it had on defense and it took heavy losses without weakening the Catholic army substantially enough. My army was reduced to a size that would be suicide to attack the Catholics again with. The warscore was raised even higher against me.
I had been keeping an eye on the Pruthenians while this all happened. Instead of marching to link their army to mine at any point where it would have been a good idea, they instead sat in place in Pruthenia long after their army morale was at 100%. They continued to sit there up until my army was engaged in it's ill fated assault on the Catholic siege camp. If they had been a part of the assault, I'm fairly certain the battle would have turned out differently.
However, as soon as my army was fighting, they began to march. Unfortunately by the time they reached the county bordering the one the Catholics were besieging, my army of my own forces and Slavic allies was effectively destroyed and it plus the Pruthenians were outnumbered by the Catholics. The Catholics caught the Pruthenian army and wrecked it, pushing the warscore to 100%.
I'm not sure if the Catholics even completed a siege of any of my holdings, and now I've lost a little under half my realm to a mid level power I can't beat without the rest of the Slavic world because of what I can only assume is an annoying bug wherein allies are missing some kind of trigger to merge with non-adjacent allies. I assume there is a trigger functioning that sends them marching when an allied army starts fighting, and another trigger that sends them to march and link to an allied army in an adjacent County.
I will pass on this word of advice; if you rely on allies in your wars make sure you march one of your armies to their borders. After you do that, they will march to your army and link themselves to it. Otherwise their armies will sit in whatever County they merge their units in until one of your armies is under attack, at which point they march and will be too late unless they are quite close.
I've noticed is that if you raid a realm that is already at war, it will cause the provinces near the raiders to raise their levies. These levies will then appear to go off to fight in the war the realm was already engaged in once the raiders retreat to safe territory, though I might be incorrect as I can't track what they do with these new levies. If it is true though, you can 'encourage' the realm your are invading to reinforce itself.
A final bug, or rather a problem regarding the potency of the AI, is that the AI is not very good at countering player controlled raiders that raid a large realm. By the time they consolidate enough to destroy my raiders, I can be back in my own territory and disband the levy, at which point they ignore me. This means it's very easy and safe to raid counties for whatever gold is not protected by fortifications over and over again by retreating back to safety as soon as there is 0 loot available. The only counter I've seen is when Bulgaria parked it's retinues right where my raiders liked to raid, or more dangerously just out of sight of my borders like a trap; however it only happened seemingly almost on accident when the retinues responded to a raid and didn't leave that province until Bulgaria's next war. In a small but comparable power realm they have an easier time consolidating, but I still often escape before they attack my raiders though sometimes I have to leave some shiny loot behind.
I started as the Count of Sacz in Poland ...
Very nice story...and that is why nobody should give up too early in any game (or life). There could be a chance to turn the table around.
Thank you for the kind words, and I agree that one should never stop striving. I will keep this in mind while continuing this game.