Background.
Cairhien became an independent nation at the end of the War of the Hundred Years.
In 566NE the Silk Path right was granted.

I'm wondering why it took the Aiel until then, and also, what was different in 566NE than in any other year? Not to mention the fact that the Guide gives a different date in Chapter 14.

Aiel War of 976-978NE.
In 998NE the granaries burned and King Galldrian was assassinated, a little over a year later the Aiel again emerged.

The Great Game : It was the nobles of Cairhien who took the style of intrigue created by the White Tower and gave it their own twist, making it into what is now known as Daes Dae'mar.

Capital : The modern city is laid out in a precise grid pattern within the perfect square formed by the high gray perimeter walls.
Foregaters. King Galldrian provided grain to feed them and all manner of parades and festivals to keep them from thoughts of uprising.

Appearance.
The people are shorter and more pale-skinned than Andorans, though with darker hair.

Cairhienin Dress Code.
Men and women wear coats or dresses of black or dark blue or green.
The number of colour slashes indicates their rank, while the colour indicate the House.
The ladies wear their hair tightly coiffed into elaborate towers of curls carefully designed to be unique to the wearer. The men wear their hair long.
Ladies skirts are extremely wide and supported by hoops.

Officers shave the front of their heads and often dust it with white powder, leaving their hair hanging long in the back. Regular soldiers wear their hair cut short in a basic bowl cut.
Cairhienin officers also wear small banners called con on short staffs on their backs.