Could you explain the Versailles strategy

Sure.

The Versailles strategy – which isn’t unique to Early Modern France; I think the sankin-kōtai system of the Tokugawa shogunate is similar enough in purpose and effect that it qualifies – was a strategy for monarchies to gain power over the nobility through the exercise of (mostly) soft power, rather than crushing them by military force.

The basic idea is this: bring the whole of the nobility together into a very large court (the court at Versailles included 6,000-7,000 people when you add together the royal family, royal officials, courtiers, and servants; compare this to the early medieval court of Charlesmagne, which amounted to a few hundred people). Instead of the king going out on progress to visit his subjects, his subjects would come to live at Versailles instead.

This change had a number of consequences:

Reduction of the economic independence of the nobility: Living at Versailles in the style benefiting a nobleman or noblewoman was incredibly expensive. Not only did it require you to establish a second household – with Louis XIV as your landlord charging you rent – but the official rules of Versailles required a particularly high-spending lifestyle: “The king insisted that every courtier be well dressed on all occasions: a death, a birthday, or a marriage in his family required that everyone wear new clothes.” (Versailles: A History, Robert Abrams) Moreover, while you were away at Versailles, you weren’t spending time on your estate maximizing your income, and the scissors of increasing spending and stagnant or declining incomes trapped a lot of the nobility in debt.
And once you were in debt, you were in Louis’ clutches. Because working was out of the question, the only way to earn additional money to help pay off your debts was through a royal post or the like, and those were Louis’ to give and take away. Moreover, residents of Versailles were spared from various forms of taxation and were legally protected from having their property seized for non-payment of debt – this is how Louis initially enticed the nobility to move – but that meant that at any time, Louis could evict you from Versailles and throw you to the wolves.

Reduction in the political independence of the nobility: at the same time, living away from your base of power meant that you became less important back at home. After all, you weren’t there making all the of the important day-to-day decisions, but the King’s intendant was.
More importantly, living in Versailles meant that the king controlled your political environment. While you might think that being surrounded by the rest of the nobility of France in close physical proximity to the King’s person might give rise to assassination or coup d’état, the reality was that you were living in the King’s palace surrounded by his guards and very far away from your feudal levies, and you had to obey his rules, which by the way kept you constantly busy in various rituals and ceremonies from the time the king got up in the morning to the time he went to bed at night, and let the king observe who was there and who wasn’t. And if that wasn’t enough to keep people loyal, he also had his spies open everyone’s mail, and listen at everyone’s doors, and he could order you arrested at pretty much any time he wanted?

So why would anyone sign up for this system?

Well, in addition to those nice taxation and debt privileges, Louis simply made it a requirement that if you wanted anything from the king – command in his armies, help with public works in your area, help with a legal case, etc. – you had to come and ask him in person. Which meant coming to Versailles and taking part in the rituals, and since getting an audience took forever, you’d better get an apartment, and so it goes…

Just as importantly, after a certain point, it was the place that the nobility wanted to live. Did you want to make a good marriage? Versailles was where the most eligible matches lived. Did you want to live a magnificent lifestyle? Louis spent a LOT of money on making Versailles the most ostentatious and magnificent palace in Europe, not just in terms of architecture and gardens, but the best entertainments, the best scholars and artists, the best tailors and craftsmen, and so on and so forth. Did you want a political career? You couldn’t really do it out in the provinces anymore, so you might as well go to Versailles and play the game.

Hello, Do you know any “rules” about wealth that make a noble person seem cultured/refined/ect? What would be considered nouveau riche and garish? Things with jewelry, food, clothing, horses would be nice to know. I mean this in context of ASOIAF/medieval and not today’s standards. The Lannisters are ridiculously wealthy, but since they are an old money family would they make big displays of wealth like the Tyrells? The Tyrells seem to use their wealth to deal with people who covet Highgarden.

The tricky thing is that there were different fashions for this kind of thing that changed dramatically over the course of the Middle Ages, the Early Modern period, etc – especially when you factor in the complicating factor of commoners getting richer than nobles by getting their hands dirty “in trade,” which makes the dividing line harder to enforce.

So for example, big displays of wealth could be very “on-brand” at various times, because nobles are supposed to be “magnificent.” This fashion obviously works in a context in which commoners either can’t afford to keep up with their betters, or aren’t legally allowed to due to sumptuary laws. At other times, understatement and the display of refined aesthetic might be considered the mark of true nobility – this fashion works in a context in which merchants, the rising bourgeoisie, etc. have tons of money but don’t have the social and cultural capital to know the “right” way to display it.

In general, I would say that some good rules of thumb for refinement are:

Don’t Talk About the Price Tag: regardless of what the fashion is about the degree of opulence at the moment, one of the key attitudes of the nobility w/r/t money is that you don’t care how much stuff costs, because you’re supposed to be stupendously wealthy, generous and open-handed, and more concerned with refined aesthetics than commercial calculation. It’s not an accident that one of the oldest tropes about “nouveau riche” is that they constantly talk about how much various things cost, because they’ve still got that bottom line mentality going on.
Know the Fashion, Know the Scene: one of the advantages of being a wealthy parasite who doesn’t work for a living is that you have a lot of spare time to do things like keep up with what’s in fashion and what’s not, what the trends are, who the best craftsmen are, etc. Especially in an aristocratic context where what’s fashionable is less decided by manufacturers and specialized press and more about what important individuals (the monarch, the monarch’s immediate family, the monarch’s mistress/mister, various long-time fixtures at court) are wearing, a lot of this knowledge is very personal and having a grasp of it is a sign that you’re close to the right people.
Making Fashion, Not Just Taking It: of course, one of the clearest signs of refinement is that the noble in question doesn’t merely follow the latest fashions but makes them, bending it to their personal aesthetic. To give an example, “Beau” Brummell was a leading aesthete of his day and, thanks to his close connections with the Prince of Wales and his own personal force of charisma, changed the dominant well-to-do men’s fashion of the day from the fop (powdered wigs anf faces, knee britches, stockings, and buckled shoes, tailcoat, lace cravats, etc.) to the dandy (hair worn naturally, clean face, long trousers, white linen cravats, frock or morning coats).

Would powerful nobles have their own courts at their personal castles, like the hightowers or redwynes or reynes would probably, but what about rowans or royces or brackens and blackwoods? what would those be like?

Absolutely. Indeed, we’ve seen examples of much smaller lords with their own courts: think about Lady Rohanne Webber, who has Septon Sefton and three septas, Maester Cerrick, Ser Lucas Inchfield her castellan, Lady Hellicent Uffering her former goodsister, a dozen knights and squires, and various pages. That’s a pretty significant household for a minor noble house.

So for lords of the Rowans or Royces or Brackens or Blackwoods, imagine that but scaled up – add on the relatives of their vassals who might serve as pages, squires, castellans, masters-of-arms, stewards, ladies-in-waiting, add on the households of other noble families who’d married into the family (except much larger households than the occasional septon or unmarried sister, because one of the ways you demonstrate how awesome you are is to have a bigger retinue than anyone else), and so on and so forth.