Apropos of castles, I've been on a look out for a hypothetical game I describe as "the thinking player's Stronghold". You would have control over a region and would need to choose the best place to site the castle, ensure supplies and build the correct structure for your location. I imagine that it would need to be modified as the attackers' technology developed.
The idea came to while walking around various forts. They're various interesting and I don't think any base-building game has really delved into them properly. Stronghold is quite superficial and Dwarf Fortress seems to focus more on the economy.
I played a lot of “Castles” (Interplay, 1991 [0]) on my 386. It was pretty simple and mostly involved getting resources and building your castle to withstand an eventual attack. It’s almost an exact description of your requirements.
It’s odd that no one has made a game that fills this same need for me in the past 30 years.
The idea came to while walking around various forts. They're various interesting and I don't think any base-building game has really delved into them properly. Stronghold is quite superficial and Dwarf Fortress seems to focus more on the economy.