Sorry for double replying/quoting, but I wanted to clarify a few potential details.
Event 1 - Infrastructure - Founding
Founded in the early days of the empire, our lands have allways been rough and untamed. The first lord was granted his title after a heroic victory against the robber barons and wildlings which occupied these lands. He built a castle to pacify the lands, and started the first mines which were the basis of future wealth (bonus defence and land)
The basic idea here works. I've set up the game so the House was actually only founded during the Blackfyre Rebellion, roughly 100 years before this game is set. Still, a great victory against clansmen, and likely supporters of the rebel bastard Daemon Blackfyre probably contributed to the award of lands and house.
Also, are you suggesting Defense and Land get the two +2d6 bonuses? Just in case you care, Mines are specifically something bought with Wealth, but do require hills and/or mountains in Lands.
Event 2 - Favor
Our house grew in influence and importance, sending it's sons and well-trained man-at-arms to battle for the king, and receiving well-earned thanks from the royal family.
Sons sent to serve the king, eh? Sounds like the house may have had a member of the Kingsguard in its short history.
Event 3 - Madness
Morniag the builder was an exception to the rule. Plagued by visions of war and slaughter that he claimed would swallow the land, he fortified the lands at great cost. This fortification would also nearly be the undoing of the familie, as the fortifications were a major target during the war.
Morniag is exactly the sort of madness the game encourages - not necessarily evil, just off and somewhat disturbed.
Event 4 - Doom
Heavy fighting destroyed much of what was built in previous generations, casualities amongst the peasants, miners and tradesmen was atrocious, valuable lands and mines were destroyed, and many inhabitants turned to banditry in order to survive. The once great house payed a hefty price indeed, it's influence and power laid low, it's wealth spent and infrastructure destroyed.
Now here's the tick. This last war was probably Robert's Rebellion/the War of the Usurper. Given that your house took heavy loses, and it's sitauted in the Vale, one of Robert's strongholds, and that the House had its founding supporting the legitimate Targaryen line, it seems likely that your House fought
against Robert while supporting King Aerys, losing much of its status in the process. It was well established in the books that Robert didn't condemn anyone for fighting well, even against him, so presumably, your House finally bent the knee to the new King Robert after he defeated Rhaegar on the Trident, which allowed them to keep some of their land and wealth, but all greatly reduced.