1. Noble Rank: King's daughters are going to be prime marriage candidates even if the king is long dead or the bride is ugly. There should be a prestige boost to the husband for marrying a woman of higher rank, and there should be some pretty big modifiers drawing potential husbands to the daughters and sisters of the more important men of the world.
2. Beauty and Charisma: The bride's personal traits should definitely play into her desirability somewhat. If your king has just married the medieval equivalent of Helen of Troy, then he should get a bonus amount of prestige equal to all the high-fives he'd be getting.
3. Dowry: A potential bride's "huge tracts of land" should be as great an incentive to the potential groom as, ahem, her other "huge tracts of land."
4. Proximity: Marrying your near neighbor's daughter should be much, much more common than going to the ends of the earth. Those should still be able to happen on occasion, but first your kingdom and the distant one need to have had some sort of reason for such contact. Royal marriages were political alliances, after all.
If a bride has all of these traits, there should then be considerable incentives to marry her. One excellent example is Eleanor of Aquitaine. She had the whole package: physically beautiful and charming, the prestigious ex-Queen of France, bordering Henry II's own lands, and bringing the whole Duchy of Aquitaine and considerable wealth to the table. These incentives should also show up in some sort of menu-- "most desirable/eligible local brides" perhaps, so that you don't have to wade through every single female in the world.
It seems very reasonable.
Nevertheless, I'd underestimate the "charm" factor, because, as others have already stated, marriages in Middle Age were mostly a socio-political issue. Then, it is true that beauty IS a factor.
And I would add a "skillfullness" carachteristic (defined as the average of all stats) because, even if is not realistic to search, as we all did in CKI, the single stats to, e.g., find that skilled steward who's missing in our realm, it is, on the other hand, true that a skilled and well-educated bride will have a better reputation than a totally inept one.
And, as someone said, it is sad, but the trait "virginity" should be included too - rulers would be less likely to marry a widow, regardless how young, skilled and powerful she might be. The sole exception could be, if female inheritance is implemented, in the case of a widow who inherits of a realm.
Of course that's not how it really worked. Parents would carefully consider the marriages of their offspring. To make the system more realistic, one could think of:
- pre-arranged marriages, i.e. the possibility of marriage contracts before both have turned 16, to be confirmed by the parents after this date (this was already proposed in another thread), and
- an official "courtship period", lasting some months or a year after the bride turned 16, during which marriage requests could be submitted and compared by the parents, resulting in a decision at the end of the period (this idea is very much like the "marriage agent" proposal, only the other way round).
Great idea, especially for the "courtship period". That will definitely stop the "first arrived, first served" system, who was quite obnoxious.
Well, if we want to have an important Duke's daughter have more status than a minor King's daughter, it can simply be based on the power & prestige of her father; although I'd also think distance should matter. Saxony may be more important than Navarra overall, but if you're a Catalan count, Saxony's a long way away.
I agree with ZanThrax too : there will be no need to rebalance the "historical importance" of kingdoms and duchies, since "prestige of the father" and "distance" can replace it quite well in game dynamics. n fact, it is maybe true than a count of Flanders "counts" more than a petty Duke of Orkney, but if my ruler is Count of Argyll, he might be politically more interested in marrying his neighbour's daughter rather than a far away beautiful and rich Dutch princess.
Being able to set terms for a marriage would also be cool. "If my daughter marries your second son, I will provide a dowry of 2400 pieces of gold. Within one year, you will make your son (my daughters husband-to-be) count of X (and duke of Y). If my daugher marries your eldest son (and heir), I will provide a dowry of 3500 pieces of gold and join you in your current war against Z." etc. etc.
Well, including marriages in diplomacy, that would be a major gain in the gameplay. But, still, I think it would be difficult to implement it in a Paradox game's typical diplomacy system. So I don't think it will be ever realised.
someone [believed to be] descended from Charlemagne or Riurik higher status than someone not; and so on.
This final remark of Calgacus leads me to another question : if CKII will be, as it seems, more dynasty-oriented than country-oriented, I suppose there will be an attribute such as "dynasty prestige". That shall definitely count on marriage system, both as a critierium of bride selection and as an issue of a good marriage (if our ruler manages to marry a high-ranked wife, his whole dynasty will benefit of a prestige bonus).
For example, if a cadet branch of Hauteville family holds the county of Taranto, and even if they're cut off every succession line outside the one as Counts of Taranto, a marriage with an Hauteville should be a peace of cake for every Italian or Norman ruler. And if my count of Corsica manages to marry the daughter of the Duke of Milan, that will mean a prestige bonus for the whole Orbetenghi family, and not just for the Corsica branch.