The title of the post will become clear at a later date, but for now, let's focus on that headdress par excellence of the episcopal order in the Western Church: the mitre.
Supposedly, it didn't come about until the tenth or eleventh century... or so, scholars and most liturgists capriciously repeat... quoting each other... over and over... as they are wont to do.
Already in the seventh century, Saint Isidore (yes, the Patron Saint of the Internet) had described them within his encyclopedic works. And no, this isn't another case of << "The problem with internet quotes is that they can't be checked" - Abraham Lincoln >> You can go to Spain and see it written in parchment and smelling of that moldy musk that only centuries-old manuscripts can afford... yet to prevent possible bubonic plague, or incarceration for doing the good old "scratch and sniff" on a priceless manuscript... here's a web-link to the first transcribed text by persons who have already gone through the motions:
The translation being along the lines of: << 6: To the priestly state also belonged the cidaris, which is called a mitre by many. >>
Cidaris [from the Greek Kidaris] was an ancient ceremonial headdress worn in Persia. Here, it is the name used for the hat worn by bishops. It should be noted that sacerdotes, which correctly translated means priests, was used in Spain to mean bishops - for these were considered "priests of the first order" (as in: they embodied the fullness of the priesthood) - whereas the "priests of the second order" were properly termed presbyters. Such it is in the Liber Ordinum, Missals, and other extant texts.
By the ninth century, we hear another well documented mention of the mitre-cidaris. This time the writer is Leovigild, a presbyter from Cordoba, who wrote a treatise on the vestments of the Catholic clergy in Spain titled "De Habitu Clericorum" - which you can reach here by downloading the pdf from the Cervantes site.
The bit that interests us at the moment, though, is this:
Which translated means: << In the episcopal ordination, the bishops use a cidaris ... and in the solemn festivities, it is placed on their head... >>
Leovigild also says that the pure-white cidaris-mitre symbolizes the white-hair of old age (canitie), and hence, why the headdress is placed on the newly-elected pontiffs [presumably as a symbol of the wisdom accumulated by those who come to have a white head...] with these words:
Inde qum in clero talis fuerit qualis apostolus designabit inuentus cidarim mundam fibrisque perfusa super caput eius inponitur ut honorem senectutis plene inter collegas uteri uideatur et uenerationem canitie ut dictum est ab hominibus tribuatur senectus inquid Sarae prolis uenerabilis est non diuturna neque annorum numero conputata cani sunt autem sensus hominis et etas senectutis uita inmaculata. Ob hanc rem canitie similis episcopi ponitur capite et a candore eius equm est uertix ipsius ornare.
And with that, we come to the first mitres... already in use some three centuries before they show up in Rome.
These were white, with red fringe hanging from the lappets, as are still used to this day. The difference is, of course, that though originally these simple mitres were used for the most solemn and festive of occasions, through the centuries, they have been relegated to be used at funerals, and by those persons privileged by the Pope to wear a mitre albeit not being ordained-bishops.
It is also worn by bishops in choir, and when acting as as concelebrants - while the principal bishop or archbishop makes use of a more ornate version which we will discuss in another post.
Cardinals, instead of the plain white-linen mitre, are themselves privileged to one made of white damask.
But what did the Popes wear before adopting the mitre?
In Rome, the popes used a camelaucium. This has more in common with the eastern-rite mitres (before they themselves took on the bulbous form common today). Originally, it was a hard cap inherited from the use of the Imperial court in Byzantium. Pre-schism, of course...
With time, it developed into the two most recognizable, and exclusive, headdresses of the papacy: the tiara, and the camauro of red velvet lined in ermine. The first, used for the liturgy, and the latter for less ceremonious occasions. The present pope prefers not to use these, so here's Saint John XXIII to illustrate 'The History of Rome':
In sum, the mitre indeed became widespread by the turn of the millennium after Rome adopted it... But they were already used 300 years earlier... by bishops in Spain - at the very least.