Medieval feast, or still a ball in the king's court?
The answer can be yes and no, because everything depends on time and environment. The cultural development of the European courts is rooted in the Duchy of Burgundy in the 15th century. But even before, during the 12th - 14th centuries in the Middle Ages, people celebrated festive events.
... And when there was a feast, people danced ... And courtiers were dancing in the court, but peasants in the village. It was a very important celebrating tradition during festive events, which also affected the Winter Solstice celebrations and, of course, also the Christmas season, relating to the influence of Christianity.
They had not yet court balls in the sense of the later centuries, but a certain beginning was already marked in the medieval culture. The idea of courtly feasts & balls has been known since the Middle Ages, when kings and queens began to organize festive events with musical accompaniment and dances at the Italian, French and English courts. Dance was the mean that allowed to show glamorous ballroom costumes and showcase the latest events of time.
In Western Europe, the prototype of ballroom dress is rooted in the tradition of wearing the most glamorous outfit. And that costume demanded an appropriate posture, courtly behavior and, of course, environment.
Truly ceremonial costumes for the first time were worn in the 15th century in the Duchy of Burgundy at the times of Duke of Burgundy, Philip the Good, because it was he who created the first courtly dress code in the history of Western Europe. Taking into account the tradition established in the Duchy of Burgundy, each of the following historical fashion styles gave special significance to the costume, the signatures of its wearing at the celebrations and feasts at the court.