If there ever was a sim game that got smashed with real time strategy and actually came out good it is Stronghold. You build your castle where you want, how you want, and then (if you're not in an economic campaign or "free build") protect it from enemy troops and animals such as bears and wolves.
Multiple play modes await in Stronghold: Military campaign (the main story), where you wage war against evil lords. Economic campaign: you have a goal to reach for goods produced and a time limit, not much story, but this campaign is in no way shape or form easy! You can siege famous castles (or custom built castles). You can test your castle building ability in the "Siege That" challenge mode where you have to hold enemies off from your custom built castle. There is also a free build mode where you can "peacefully design your ideal castle", or in my case, design a massive, ugly POS trying to expand to keep people to fill the jobs to make sure I have a steady income of resources.
There are various map packs available online (as with any game, some are excellent and better done than the base game and others are steaming piles of fail) and there are even a few mods out there to enhance gameplay.
Gameplay is simple, you need houses to get peasants, your peasants fill jobs (such as farming and processing food, gathering resources, hunting, weapon smithing, etc.) Idle peasants can be recruited into your army if you have spare peasants and spare weapons (troops do not count towards your maximum population). Build walls to defend your castle including towers (so your archers can still shoot your enemies) and gates (just don't leave them open or there's no point to the walls!) walls seem to deteriorate very quickly, so always be prepared to build new pieces in their place.
An element that reminds me a lot of Lords of the Realm is the happiness system. You can tax your people to get gold, but if you tax them too much they will become unhappy and leave the castle. There are ways of making your peasants happy, such as drowning their sorrows in ale, for example.
No matter what I day about this game I cannot do it justice, it's available at gog.comGog.comor you can get the Stronghold collection on Steam which includes every Stronghold game except the third (the newest one). If you enjoy Stronghold I would recommend checking out Stronghold 3, a lot of people were disappointed in it but that's mainly because it was too similar to the first. It is in no way shape or form worth 49.99 but if you see it on sale you'll probably enjoy it.
One final thing: one beautiful (to some people horrible) thing about this game is there is only one voice actor. This is really noticeable with the female characters, whether or not this was on purpose or due to a lack of funding I'm not sure but it gave the game a subtle humor. The soundtrack is also great.