Zoste patrikia

Zōstē patrikía () was a Byzantine court title reserved exclusively for the woman who was the chief attendant and assistant to the Empress. A very high title, its holder ranked as the first woman after the Empress herself in the imperial court. The title is attested from the 9th century until the 12th century, but only a handful of its holders are known.
History.
The title means "girded lady-patrician", often translated into English as "Mistress of the Robes", and was used for high-ranking court ladies who were attached to the Byzantine empresses as their ladies of honour. Its origin or date of institution are unclear. 
Disregarding a clearly anachronistic reference to Antonina, the wife of the great 6th-century general Belisarius, as being a "zostē patrikia", the title is first attested in for Theoktiste, the mother of Empress Theodora. 
The title is last attested in literary sources (the "Skylitzes Chronicle") in 1018, when it was conferred to Maria, the former Empress of Bulgaria, and finally in a series of lead seals dated to the late 11th century (see below). It disappears thereafter, along with many other titles of the middle Byzantine period, following the reforms of Emperor Alexios I Komnenos ().
Status and functions.
In Philotheos's "Klētorologion" of 899, the dignity of the "zostē patrikia" is placed very high in the imperial order of precedence, coming before the "magistros" and after the "kouropalatēs". Her exceptional status is further illustrated by the fact that she was one of only six dignitaries who dined at the imperial table—along with the Patriarch of Constantinople, the "Caesar", the "nōbelissimos", the "kouropalatēs" and the "basileopatōr"—and by the prominent role she played in imperial ceremonies, especially those revolving around the Empress, such as the coronation of an empress or the birth of a child. Although it appears that, in common with the other supreme dignities with which it is associated, there was a single holder of the dignity at each time, at the reception of Olga of Kiev, the plural form "zōstai" is used, indicating the presence of at least two. This may be accounted for by the fact that at times there were several empresses, and that each one must have had a "zōstē" in her particular service.
The "zōstē patrikia" functioned as the chief attendant to the empress (to whom she was usually related) and the head of the women's court (the "sekreton tōn gynaikōn"), which consisted mostly of the wives of high-ranking officials. Indeed, hers was the only specifically female dignity: other women bore the feminine versions of their husbands' titles. A "zōstē patrikia" is therefore, in John B. Bury's words, "the only lady who was πατρικία in her own right", and not to be confused with a simple "patrikia", who was the spouse or widow of a "patrikios". Indeed, the French scholar Rodolphe Guilland points out that the title itself appears to be a compound one, with the sources sometimes calling it "the "zōstē" and "patrikia"", indicating that the noble title of "patrikia" was added to the court dignity of "zōstē". 
The "zōstē" was raised to the rank in an elaborate investiture ceremony in the Theotokos of the Pharos palace chapel, which is recorded in the "De Ceremoniis" (I.50) of Emperor Constantine VII Porphyrogennetos (). The ceremony ended in the Chrysotriklinos audience hall, where she received from the emperor's hands the ivory tablets that were the particular insignium of her office. She then visited the Hagia Sophia, where the tablets were blessed by the Patriarch, before making her way to the Magnaura, where she received the congratulations of the women of the court and the spouses of the high dignitaries. Finally, she returned to the Pharos chapel, where she deposited an offering of 70 "nomismata", before retiring to her apartments. The distinctive dress of the "zōstē", which probably gave the title her name, was the broad belt or "loros" that she put on at the investiture ceremony. A descendant of the ancient Roman consular "trabea", the golden "lōros" was the "most prestigious imperial insignium", and was also worn by the Byzantine emperor and a select few of his highest dignitaries such as the Eparch of Constantinople or the "magistroi". A less likely origin of the "zōstē" may derive from her position as chief lady-in-waiting to the empress, among whose duties was to supervise her dress, or, as the "Patria of Constantinople" puts it, to "gird" the empress. 
The "zōstē" held her title for life, even after the death of an empress she had been appointed to serve. In addition, like most Byzantine titles, the dignity could be conferred as a simple honour without the requirement of service, as was most likely the case with Theoktiste and Maria, the widow of Tsar Ivan Vladislav of Bulgaria.
List of known holders.
Despite the prominence of their title, the sources mention but rarely the "zōstai". As Rodolphe Guilland writes, "confined to the women's quarters of the empress, they hardly had the opportunity to become known. Certainly the women's quarters were sometimes a hotbed of intrigue and scandal; but the noise of these intrigues and these scandals hardly crossed the walls of the Great Palace."