There are always factions at Court. Through a quirk of history and fate, the two main factions at court identify themselves with specific colors.
The Yellows have a two part agenda. First, they support a more liberal and progressive social agenda for the Kingdom. It would tax the rich a bit more (since they have money) instead allowing them to pay with feudal duty and traditional gifting. Secondly, they support The Duke as the next King. He is one of three contenders for the crown when the aged King dies (having outlived all three of his children). His claim is not the strongest by blood, but the strongest in capability. The Duke is supporting this agenda, trying to move his country away for simple feudalism.
The Yellows get their name partially from the Duke’s coat of arms, which is primarily yellow, partially from the yellow regions of the map (which is where the exchequer’s office designates rich areas not doing feudal duty). Members tend to have yellow feature prominently in their clothing, or have a yellow hankerchef, or wear a yellow armband with a royal crest on it).
The Yellows are now opposed by The Blues.
The Blues represent the old guard, those who want the status quo. They want things the way they were decades ago (if not centuries ago), when many of its members remember or think there were ‘better days’ (when their houses had more privilages). If things change, these members feel they have much to loose, so they are protecting their ass so to speak.
The Blues support the Viceroy who is the King’s closest relative, on his mother’s side. They show their support by wearing blue to court. (The Blue comes from the old color of “nobility” in the region, as well as the colors of the Viceroy).
Now this piece is attached to the Magenta Rose series, but you can insert these “teams” into any court. And do not forget The Greens of the Colors.