What was the name of the costume in the courts of medieval Europe?

Called "Byzantine dress".

Byzantine style clothing in medieval Europe inherited and developed the civilization and art of ancient Greece and Rome.

At the same time and a combination of the Orient's exquisite and gorgeous embroidery patterns, and silk for the noble and fashionable.

In the Middle Ages, only the nobility were allowed to wear red coats, which were cut like robes, with bell-shaped pleats and wide sleeves, and were called schaubes (schaube), a typical garment of the Middle Ages.

Anyone who dared to wear a red color that was not in keeping with his status was punished by death.

Explained

Byzantium was an ancient Greek city, the former name of present-day Istanbul, Turkey, which was generally referred to simply as the "Roman Empire" throughout its millennia-long existence.

During the Byzantine period, as Christianity became more widespread, clothing shifted its focus to the texture, color, and ornamentation of the material.

Characteristics of men's clothing: closed shoes replaced the previous sandals, shawls covering most of the body, and square or rectangular embroidery on the front and back.

Characteristics of women's clothing: more oriental than men's, with many pearls, precious stones, clothing is also very gorgeous, using gold thread woven.