Medieval manuscripts blog

Bringing our medieval manuscripts to life

18 August 2022

The man with the golden bulla

Our current Gold exhibition includes a number of the Library’s most famous treasures, but it also contains some little-known gems. One of the objects that was most fun to research is also one of the least familiar: the golden bulla of Baldwin II, Latin Emperor of Constantinople, attached to a land grant from May 1269. When I first came across this item while scoping for the exhibition, I had never seen a golden bulla before, nor had I heard of the Latin Emperors of Constantinople. But a bit of digging turned up the fascinating story of a failed emperor and his golden self-promotion.

A medieval charter with a gold seal attached to the bottom by red cords
Charter and golden bulla of Baldwin II, Latin Emperor of Constantinople (Biervliet, May 1269): Add Ch 14365

What is a golden bulla?

In medieval Europe people authenticated documents by attaching a seal impressed with their unique design. Usually these seals were made from wax, but occasionally they were made from metals such as lead or gold. These metal seals were known as bullae (from the Latin for ‘bubble’) and were generally reserved for the most prestigious papal and imperial documents.

The use of golden bullae to seal documents is associated most closely with the Byzantine Emperors. The Byzantine Empire was the Greek-speaking eastern half of the Roman Empire which continued as a major power until 1453, when its capital, Constantinople (present-day Istanbul), fell to the Ottoman Empire. The golden seal, or chrysobull in Greek, was an effective emblem of Byzantine government, used by the emperor to authorise formal documents such as diplomatic correspondence, decrees of law and grants of privileges. The earliest surviving examples are from the Byzantine Emperor Basil I (r. 866-86).

A Byzantine gold seal, showing two figures holding a military standard, with inscriptions round the edges
Gold seal of the Byzantine Emperor Basil I, depicted with his eldest son Constantine (Constantinople, 866-86) (Source: The British Museum © The Trustees of the British Museum)

Some western rulers imitated the Byzantine practice of sealing important documents in gold, especially the Holy Roman Emperors. The British Library holds just one other medieval golden bulla, that of Holy Roman Emperor Frederick III (r. 1440-1493).

A gold seal showing a enthroned emperor, with inscriptions around the edges
Gold seal of Holy Roman Emperor Frederick III (Germany, 1440-1493): Seal XLIII.161

The high material value of golden bullae meant that they were frequently melted down and reused. For example, in the 11th century the Holy Roman Emperor Henry III gave a letter from the Byzantine Emperor Constantine IX to the church at Goslar, where the gold bulla was melted down to make a chalice (as recorded in the Chronicon Sanctorum Simonis et Judae Goslariense). With their restricted use and low survival rate, medieval gold bullae are extremely rare today.

Who was Baldwin II, Latin Emperor of Constantinople?

The golden bulla that features in the Gold exhibition is particularly fascinating because it was not issued by a Byzantine emperor, but by a man who was pretending to be one. In 1204, during the Fourth Crusade, a crusader army from western Europe captured the Byzantine capital of Constantinople. The crusaders founded a new Latin Empire of Constantinople with one of their leaders, Baldwin of Flanders, as emperor. His Flemish family ruled Constantinople for the next 57 years until the city was retaken by the Byzantine Greeks in 1261. The final Latin Emperor of Constantinople was Baldwin II, nephew of the first emperor and issuer of our golden bulla.

Baldwin II was born in Constantinople in 1217 and became Latin Emperor in 1228 at the age of eleven. He spent his reign struggling to hold onto power and desperately attempting to raise funds from western rulers. Perhaps his most notable legacy is that he sold one of the most holy Christian relics, the Crown of Thorns, formerly kept in Constantinople, to King Louis IX of France, who built the royal chapel of Sainte-Chapelle to receive it. The relic was preserved at the Cathedral of Notre Dame in Paris until the fire of 2019, when it was rescued from the blaze and moved to the Louvre.

Medieval miniature showing King Louis receiving the Crown of Thorns and other relics from a group of churchmen
Louis IX receiving the Crown of Thorns and other relics from Constantinople, Les Grandes chroniques de France (Paris, 1332-1350): Royal MS 16 G VI, f. 395r


The Crown of Thorns
The Crown of Thorns, encased in a circular crystal reliquary of 1896, the Cathedral of Notre Dame, Paris (Source: Wikimedia / CC BY-SA 3.0)

Baldwin’s reign came to an end on the night of 24 July 1261 when Greek Byzantine soldiers launched a surprise attack and recaptured Constantinople. Luckily, Baldwin and many other inhabitants were rescued by the Venetian fleet. Although he spent the rest of his life in exile in western Europe, Baldwin never gave up his claim to the throne of Constantinople nor stopped using the title of emperor.

Decoding Baldwin’s golden bulla

The golden bulla at the British Library dates from after Baldwin was deposed and fled west. The charter to which it is attached was issued in May 1269 at Biervliet, a small town in the Netherlands. In it, Baldwin confirmed the grant of lands at Biervliet by his uncle, Philip I, Marquis of Namur, to the church of St Bavo in Ghent. The seal is made from two thin gold plates, each stamped with a different design, then joined together, rather like the foil on a chocolate coin. It is affixed to the document with red silk cords which pass through the interior of the bulla between the two plates.

Although the charter deals with the administration of Baldwin’s ancestral lands in Flanders, its gold seal speaks of his pretensions in Constantinople. The rare use of the golden bulla emulates Byzantine imperial practice, and the images and inscriptions reinforce Baldwin’s claim to be emperor.

The front of the seal shows Baldwin seated on a throne in full Byzantine regalia. He wears a Byzantine-style crown with pendilia (hanging ornaments) and holds the imperial sceptre and globe. He also wears a loros, an embroidered cloth wrapped around the torso and draped over the left arm. The Latin inscription reads:


(Baldwin Augustus, by the grace of God, Emperor of Romania forever).

Romania (‘the land of the Romans’) was one of the contemporary names given to the Latin Empire of Constantinople, which was claimed to be the second Rome and the legitimate heir of the Roman Empire.

The front of the golden bulla, showing Baldwin seated on a throne, holding the orb and sceptre and weating a crown and loros, with a Latin inscription around the edge
The golden bulla of Baldwin II (Biervliet, May 1269): Add Ch 14365, obverse

The reverse of the bulla shows Baldwin on horseback bearing the Byzantine crown and sceptre, perhaps as a reference to the famous equestrian statue of Emperor Justinian I (r. 527-565) that stood in the main square of Constantinople in the Middle Ages. Remarkably for a seal issued in the Netherlands, the inscription on this side is in Greek. It reads:


(Baldoinos despotes Porphyrogennetos Phlandras / Baldwin the Ruler, purple-born, from Flanders).

The term Porphyrogennetos (‘born in the purple’) was used to refer to individuals born legitimately to a reigning emperor. The term was said to refer to the porphyry chamber in the imperial palace of Constantinople where empresses traditionally gave birth. Baldwin’s description of himself as Porphyrogennetos emphasises his birth-right as a Byzantine emperor as well as his birth location in the imperial palace in Constantinople.

The reverse of the golden bulla, showing Baldwin on horseback with the crown and sceptre, with a Greek inscription round the edge
The golden bulla of Baldwin II (Biervliet, May 1269): Add Ch 14365, reverse

They say that all that glisters is not gold. Baldwin’s bulla is certainly golden, but the message of imperial power it conveys is illusory. By the time it was issued, the crown of Constantinople was firmly planted on another man's head. Still, this rare object is fascinating for its cross-cultural mix of features and its insight into one man’s construction of a public persona at odds with reality.

The British Library’s Gold exhibition runs until 2 October 2022. You can book tickets online now. An accompanying book Gold: Spectacular Manuscripts from Around the World is available from the British Library shop.

Eleanor Jackson
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Supported by:

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The exhibition is supported by the Goldhammer Foundation and the American Trust for the British Library, with thanks to The John S Cohen Foundation, The Finnis Scott Foundation, the Owen Family Trust and all supporters who wish to remain anonymous.