Jewels with history I: The Black Prince's Ruby, from a Castilian king to the British crown

When Queen Victoria ascended to thethrone of the United Kingdom in 1838 at just 18 years old, she decided to wear a new crown at the ceremony in which she was invested as sovereign. Instead of the St. Edward's Crown, the piece that was traditionally used until then, Victoria was enthroned with a new and spectacular crown composed of 2,868 diamonds, 273 pearls, 17 sapphires, 11 emeralds and 5 rubies . At the center of that marvel, in the most striking and splendid place of the crown that would from then on be used in the enthronement ceremonies of British monarchs, was placed the so-called Black Prince Ruby .

This is a deep red stone that isn't actually a ruby, but a spinel , a rarer gemstone that can be even more valuable than a ruby. The British Crown Diamond is uncut, only lightly polished, and one of the largest in the world, with an estimated weight of 170 carats and a length of almost 5 centimeters. This gem has belonged to the British royal family since 1367, but was previously owned by a Spanish king. This is its story.

The Black Prince's Ruby, as it is still known despite the fact that it is in fact a spinel, almost certainly originates from the mines of Badakhshan , in northeastern Afghanistan , very close to the border with Tajikistan . It probably reached Europe, and more specifically Granada , via the Silk Road and Genoese merchants.

The jewel was a witness to the power struggles to seize the throne of Granada that began in 1359 when Muhammad V , ruler of the Muslim kingdom, was overthrown in a coup d'état that crowned his brother, Ismail II , in his place. But Ismail II's reign was short-lived: he was assassinated by his cousin, who became king as Muhammad VI .

But Muhammad V did not sit idly by after being overthrown. He managed to convince Peter I of Castile , known by the nickname "The Cruel," to help him recover the kingdom of Granada, establishing a military alliance between the two sovereigns. The agreement seemed advantageous to Peter I, especially given that he himself was facing an internal rebellion led by his half-brother Henry of Trastámara , who was increasingly gaining support from more and more Castilian nobles, so it seemed like a good idea to lend a hand to Muhammad V. With his support, the deposed king of Granada gradually gained ground and, with his soldiers, was dangerously approaching the city and the throne from which he had been expelled.

Faced with the advance of Muhammad V, the new ruler of Granada opted for a risky decision. Muhammad VI decided to present himself before Pedro I and try to convince him to stop supporting his cousin and instead back him. And, to try to tip the balance in his favor, he thought it appropriate to present the Castilian king with a small treasure that included three important rubies.

Muhammad VI's plan failed miserably. Pedro I was satisfied with his alliance with Muhammad V and had no intention of breaking it, so he had Muhammad VI arrested during a banquet, personally murdered him with a spear, and took the jewels . All these events were recorded by Pedro López de Ayala in his Chronicle of King Pedro, the first text to refer to the famous ruby.

But, some years later, it was Peter I of Castile himself who, seeing his power seriously shaken at the hands of his half-brother Henry of Trastámara, was forced to ask for help. He obtained the support of Edward of Woodstock , the heir to the throne of England, nicknamed the Black Prince because of the armor of that color he used to wear and who until then had a long record of military victories. The alliance was forged and in exchange for his military support, Peter I agreed to provide military support to the Black Prince in his campaigns against France, to give him the Lordship of Biscay and the town of Castro Urdiales and to share with him the spoils of war that were obtained.

Edward of Woodstock did his part and, with his undeniable military skills, he conquered one after another all the towns that had rebelled against the Castilian king. On April 3, 1367, he declared himself the victor in the Battle of Nájera, which was a terrible defeat for Henry of Trastámara . The one who did not comply was Peter I, who refused to pay the Black Prince the agreed amount. Edward of Woodstock, who had borne the enormous expenses of the Castilian campaign, was left completely ruined. He left Spain impoverished and in very poor health.

“With him, he carried the few jewels that the Castilian king had agreed to give him in payment for his services, a negligible sum compared to the enormous expenses the Black Prince had incurred. Among them was the ruby that Pedro I had forcibly seized from the king of Granada,” notes writer and art and antiques appraiser Ana Trigo in her fascinating book. Cursed Jewels (La Esfera de los Libros), which reviews the history of some of the world's most famous gems.

The red spinel thus became part of the British Crown Jewels and was the property of successive British monarchs. The jewel became known as the Black Prince's Ruby in memory of Edward of Woodstock, the man responsible for ensuring that the gem was added to the British Crown Treasury.

But Pedro I's failure to comply with his agreement with the Black Prince ended up costing him dearly: his half-brother Henry of Trastámara, who managed to escape with his life after the crushing defeat he suffered at the Battle of Nájera , managed to raise a new army. And when Pedro I tried to seek help again, this time no one offered it, remembering how he had behaved towards the heir to the British throne. In 1369, at the age of 34, he was assassinated by Henry of Trastámara himself. Edward of Woodstock, meanwhile, never reigned ; he died in 1376 at the age of 45, probably from dysentery that he had contracted in Spain.

The Black Prince's Ruby was worn by several English kings in their war helmets , following the custom of the time for sovereigns to be magnificently equipped for the battlefield and wearing rich insignia that made them easily recognizable. The jewel was passed from king to king until James I of Scotland , the first monarch of the Stuart dynasty, who decided to mount the ruby in the official state crown.

Following the rebellion led by Oliver Cromwell against King Charles I , which resulted in the king's execution in 1649 and the temporary abolition of the monarchy, the ruby was sold along with almost all the crown jewels. But when Charles II , the son of the executed Charles I, regained the throne in 1660 and the monarchy was restored, the ruby reappeared in the hands of an anonymous seller who offered it to the king. Charles II agreed to buy it, and when he again owned the jewel, he ordered it to be set into the state crown. Many years later, Queen Victoria would make it the centerpiece of the new crown she commissioned for her accession ceremony, and which has been worn by all British sovereigns ever since on the most important occasions . But once, more than six centuries ago, that blood-red stone belonged to a Castilian king.