Amongst a glittering treasury of splendours, the Habsburgs revered two objects above all others. One was a bowl reputed to be the Holy Grail and the other was a unicorn’s horn.
A truly Imperial collection
The Habsburgs were amongst Europe’s pre-eminent collectors. They collected titles (from the Count of Habsburg to the Holy Roman Emperor with a host of dukedoms, royal and imperial titles in-between), lands (by 1700, Habsburgs ruled Spain, southern Italy, Milan, Austria, Hungary, Bohemia and Flanders) and brides (a favoured motto for the family was bella gerant alii, tu felix Austria nube (let others wage war; you, happy Austria, marry) .
But of the many things that the Habsburgs collected, nothing captured the imagination like the riches of the Imperial Treasury. And, of these, the two ‘inalienable heirlooms of the House of Austria’ were the most precious. They were the finest objects in the thaumaturgical collection – the Holy Grail and a sceptre forged from a unicorn’s horn.
Compared with these treasures, the crown jewels of other countries were merely shiny trinkets. These were the rarest, holiest and most potent symbols of the preeminence of the Habsburgs. They were accorded solemn and divine status. A binding contract, similar to a deed, ensured that they would stay in the family. And, inevitably, they were both fakes.
The Holy Grail?
According to legend, the Holy Grail was the vessel that caught the blood of Jesus Christ as he hung on the cross. Over the centuries, it was imagined as a cup, goblet or bowl. It inspired art and literature, with a written record stretching back to Chrétien de Troyes’s Perceval written at the end of the twelfth century.
According to the Habsburgs, the Holy Grail was their very own Agate Bowl (Achatschale). This immense object was hewn from a single piece of agate. It remains the largest carved stone bowl in the world.
The scale was impressive, but the workmanship made it unrivalled. The stone was polished until it gleamed with a translucent glow. It has an iridescent brilliance that seems to capture light and colour. These characteristics alone made it a prized object.
What transformed it into a holy relic was a mysterious inscription embedded in the very veins of the agate. In a certain light, the letters XRISTO could be seen.
A unicorn’s horn?
Unicorns are mythical animals with potent symbolism in European legends. They are typically depicted as horses distinguished by a single straight horn protruding from their foreheads.
They were wild, untameable beasts which could only be captured by a pure and chaste virgin. In allegorical stories, tapestries and tableaux, the entrapment of a unicorn was symbolic of the Passion of Christ. In the 1470s, Leonardo da Vinci drew a maiden with a unicorn. In his notebook, he explained:
The unicorn … because of its intemperance, not knowing how to control itself before the delight it feels towards maidens, forgets its ferocity and wildness, and casting aside all fear it will go up to the seated maiden and sleep in her lap, and thus the hunter takes it .
The Habsburgs were keen to bolster the family’s image of holiness. This was more than a sign of devotion. It was an integral component of their most important title as Holy Roman Emperors. A unicorn’s horn was, therefore, an impressive sign of the owner’s standing in the Christian faith. So it wasn’t a great leap for the family to incorporate a unicorn’s horn into their sceptre.
The two most essential items in any set of European crown jewels are the crown and sceptre. Five public houses are named the Crown and Sceptre in Greater London alone . The sceptre represents authority and power. It is analogous to a staff, rod or wand of office. The sceptre of the House of Austria certainly conveys that impression.
The sceptre’s magnificent head is worked in enamelled gold. It is topped by a large sapphire, a nod to similar stones set in the Crown and the Imperial Orb. Exquisite work by the Imperial goldsmith incorporates diamonds, rubies, pearls and emeralds .
But it is the simple shaft that was the most important element for the Habsburgs. This was the section of the Sceptre that had been fashioned from the horn of a unicorn. This Ainkhürn, or alicorn was amongst the most valuable objects that a medieval monarch could possess.
A more mundane beast
What was to stop a spendthrift monarch pawning these otherwise priceless treasures? How could the family prevent their most precious possessions ending up outside of their control? The answer was a legal covenant.
As Manfred Leithe-Jasper writes in his encyclopaedic reference work on the Imperial and Ecclesiastical Treasury:
Their cultural value was deemed so important that, after Ferdinand I’s death in 1564, his sons declared them to be “inalienable heirlooms of the house of Austria” 
In fact, the first documented reference of the Agate Bowl is in this deed, dated in 1564 and executed by Holy Roman Emperor Maximillian II and his brothers. In it, they declared the bowl to be an “inalienable heirloom of the house of Austria”. From that date onwards, they were the property of the entire dynasty, now and forever.
Today, they are part of the Kunsthistorisches Museum Wien’s most impressive collection of imperial objects. The museum now describes the ‘Holy Grail’ as The Agate Bowl. The unicorn’s horn, the shaft of the Imperial Sceptre, is now recognised as the tusk of a rather more mundane beast – the narwhal.
 Brook-Shepherd, Gordon. The Austrians: A Thousand-year Odyssey. New York: Carroll & Graf Publishers, 1997 (click here). A longer and more poetic iteration of this motto was, ‘Leave the waging of wars to others! But you, happy Austria, marry; for the realms which Mars awards to others, Venus transfers to you.’
 “Universal Leonardo: Leonardo Da Vinci Online.” Young Woman Seated in a Landscape with a Unicorn. Accessed September 29, 2016. http://www.universalleonardo.org/work.php?id=438.
Description of a pen and ink sketch by Leonardo da Vinci at the Ashmolean Museum, Oxford
 Adams, John. “The Listed Pubs of London.” The Listed Pubs of London. Accessed September 29, 2016. http://www.ucl.ac.uk/ccaajpa/pubs-listed.html.
 “Sceptre – Andreas Osenbruck.” Google Cultural Institute. Accessed September 29, 2016. https://www.google.com/culturalinstitute/beta/u/0/asset/sceptre/DgFIvTi36arw6A.
From the collection of the Imperial Treasury, Kunsthistorisches Museum Wien
 Leithe-Jasper, Manfred, Rudolf Distelberger, and Dinah Livingstone. The Kunsthistorisches Museum Vienna: The Imperial and Ecclestiastical Treasury. Vol. 1. (München: Beck, 1998), 7 (click here) .