ranked above crimson. Several changes to the ranks of colors occurred after that time. Purple in the Byzantine Empire and Carolingian Europe Through the early Christian era, the rulers of the Byzantine Empire continued the use of purple as the imperial color, for diplomatic gifts, and even for imperial documents and the pages of the Bible. Gospel manuscripts were written in gold lettering on parchment that was colored Tyrian purple. Empresses gave birth in the Purple Chamber, and the emperors born there were known as "born to the purple," to separate them from emperors who won or seized the title through political intrigue or military force. Bishops of the Byzantine church wore white robes with stripes of purple, while government officials wore squares of purple fabric to show their rank. In western Europe, the Emperor Charlemagne was crowned in 800 wearing a mantle of Tyrian purple, and was buried in 814 in a shroud of the same color, which still exists (see below). However, after the fall of Constantinople to the Ottoman Turks in 1453, the color lost its imperial status. The great dye works of Constantinople were destroyed, and gradually scarlet, made with dye from the cochineal insect, became the royal color in Europe. The Middle Ages and Renaissance In 1464, Pope Paul II decreed that cardinals should no longer wear Tyrian purple, and instead wear scarlet, from kermes and alum, since the dye from Byzantium was no longer available. Bishops and archbishops, of a lower status than cardinals, were assigned the color purple, but not the rich Tyrian purple. They wore cloth dyed first with the less expensive indigo blue, then overlaid with red made from kermes dye. While purple was worn less frequently by Medieval and Renaissance kings and princes, it was worn by the professors of many of Europe's new universities. Their robes were modeled after those of the clergy, and they often wore square/violet or purple/violet caps and robes, or black robes with purple/violet trim. Purple/violet robes were particularly worn by students of divinity. Purple and/or violet also played an important part in the religious paintings of the Renaissance. Angels and the Virgin Mary were often portrayed wearing purple or violet robes. 18th and 19th centuries In the 18th century, purple was still worn on occasion by Catherine the Great and other rulers, by bishops and, in lighter shades, by members of the aristocracy, but