A rare Medieval Vestment: the Rationale

Let's explore last week's rationale a bit more. This rare medieval vestment is modelled on the ephod of the Jewish high-priest. Chapter 28 of the bible book Exodus described the garments that need to be made by skilled craftsmen for Aaron and his sons in great detail. Verses 6-14 tell us about the design of the ephod:
"And they shall make the ephod of gold, and violet, and purple, and scarlet twice dyed, and fine twisted linen, embroidered with divers colours. It shall have the two edges joined in the top on both sides, that they may be closed together. The very workmanship also and all the variety of the work shall be of gold, and violet, and purple, and scarlet twice dyed, and fine twisted linen. And thou shalt take two onyx stones, and shalt grave on them the names of the children of Israel: Six names on one stone, and the other six on the other, according to the order of their birth. With the work of an engraver and the graving of a jeweller, thou shalt engrave them with the names of the children of Israel, set in gold and compassed about: And thou shalt put them in both sides of the ephod, a memorial for the children of Israel. And Aaron shall bear their names before the Lord upon both shoulders, for a remembrance. Thou shalt make also hooks of gold. And two little chains of the purest gold linked one to another, which thou shalt put into the hooks." (Douay-Rheims Bible which is closest to the Vulgate Latin version widely used in medieval Europe).
The text makes clear that the ephod was a very precious garment with gold, gemstones and costly dye-stuffs. And it also explains the shape of the medieval rationale with the two patches on the shoulders. The name "rationale" is derived from the translation of the priest's ephod (Hebrew), to logion (Greek) into rationale (vulgate Latin) (Miller 2014, 64).

Front of the Regensburger rationale held at the Regensburger Domschatz.

Who was allowed to wear a rationale? Bishops were allowed to wear the rationale over the chasuble. Although it seems that this special vestment was sometimes granted by the pope to a particular bishop (Pope Agapetus II apparently granted one to the see of Halberstadt, Germany, before AD 984) other bishops simply copied its use. It became fashionable in the 11th- and 12th- century in Germany and then spread to France and England in the 13th-century. Curiously, Italian bishops, with the exception of the sees of Aquileia and Monreale, do not seem to have been keen on wearing it (Miller 2014, 65-66). Presently, only the bishops of Eichstätt and Paderborn (Germany), Toul-Nancy (France) and Krakow (Poland) wear this medieval vestment on special occasions.

The rationale from Bamberg belongs to the so-called Kaisergewänder (held at the Diözesanmuseum Bamberg) and was made between AD 1007 and 1024 in the realm of Holy Roman Emperor Henry II. The embroidery is made with very fine, near-pure goldthreads in normal couching on dark-blue silk samite imported from the Byzantine Empire. Although presently the embroidery is applied to a bell-chasuble made of blue Italian silk damask from AD 1450, the original embroidery was also part of a bell-chasuble rather than a separate vestment such as the Regensburger rationale. The embroidery depicts scenes from the Apocalypse, an allegory of the church and busts of the apostles (Kohwagner-Nikolai 2020, 190-196).

The rationale from Regensburg (part of the Regensburger Domschatz) was made in AD 1314/1325, possibly in Regensburg (Germany). It was made at the behest of king, and later Holy Roman Emperor, Louis IV, called the Bavarian (AD 1282-1347). He gifted it to bishop Nikolaus von Ybbs (AD 1270/1280-1340), bishop of Regensburg. It is made of linen embroidered with very fine gold- and silver threads as well as silks. On the front, we see an allegorical depiction of the church. On the back, we see Christ in the mandorla surrounded by angels, symbols of the evangelists and the agnus dei. The elongated slips on the front and the back contain the busts of the apostles. The two shields on the shoulders contain female allegories of Psalm 85:10. Each depiction can be identified by stitched texts in either Latin or German (Kohwagner-Nikolai 2020, 237-240).

For a detailed description of the embroidery techniques and materials used for both rationale, we will have to wait for the publication of the research project results of the "Kaisergewänder", later this year.

Literature
Kohwagner-Nikolai, T., 2020. Kaisergewänder im Wandel - Goldgestickte Vergangenheitsinszenierung. Regensburg: Schnell & Steiner.
Miller, M.C., 2014. Clothing the clergy. Cornell University Press.