In 1704, Dutch trader Wilhem Bosman published his account of 13 years spent on the Gold Coast / Coast of Mina, located on the shores of modern Ghana. Translated into English and French within a year of its publication, Bosman’s A New and Accurate Description of the Coast of Guinea quickly became one of the most widely read travel accounts about Africa in early modern Europe. Among his observations, Bosman made frequent references to enigmatic beads he termed “accori” or “aggrey,” which he described as a highly prized variety of “coral,” a term used to denote glass beads. According to Bosman, accori beads were distinctively sky blue but had a greenish translucence, a rare property known as dichroism. These beads belonged to a broader category of sought-after beads in the Gulf of Guinea, collectively known by the Portuguese name Conte de Terra, which translates to “beads from the ground.”

Gérard Chouin

But where did these beads originate? Recent archaeological work points to Ife, a city often considered the source of the modern Yoruba civilization. Medieval Ife was a major industrial center that specialized in glass production and bead manufacture, including blue dichroic beads. Following the decline of this industry in the second half of the 14th century, the production of beads stopped, although they continued circulating as prestige items. The beads’ rarity increased their value, and ancestral sites became a source of old beads to reinject in the local and regional markets.

Their remarkable value led directly to European merchants’ fascination with the beads. When Bosman wrote of accori beads, they fetched four times their weight in gold. Although the term first appeared in Portuguese records in 1508, there is strong evidence that these beads were transported by Portuguese ships from the Bight of Benin to the Coast of Mina as early as the late 1470s. Portuguese mariners had explored the coast of what is now Ghana in 1471 and began trading in the Lagos lagoon by 1472; by the end of the 1470s, they were purchasing enslaved individuals and locally made textiles in the Gulf of Benin to exchange for gold in Elmina. The demand for accori beads had thrived long before Portuguese mariners’ arrival, and they could not have missed the small yet lucrative market.

The Portuguese were skilled mariners, but in the 15th century, Italian firms held the greatest expertise in trading with non-Christian nations. These firms had established offices in Portugal and invested in commercial opportunities within the expansive Atlantic territory shaped by the Portuguese monarchy. Consequently, Italian merchants engaged in the accori bead trade from the late 15th century. They were drawn to the substantial profits derived from reselling Conte de Terra beads but frustrated by the limited quantities their partners in the lagoons and rivers of modern southwestern Nigeria could provide.

As their name suggests, Conte de Terra beads were not a manufactured product that could be produced to meet growing demand. Instead, these unique beads were dug out from the ground or occasionally surfaced after heavy rainfall. It was a logical step to bring a few of these beads back to Venice, a city already involved in Atlantic expansion and one of Europe’s foremost glass production centers, to produce imitations on a larger scale.

In an unexpected turn of events, African beads based on a unique chemical recipe and design, and produced at Ife during the late medieval period, served as models for Venetian beads to be sold on the African market. The original accori beads are antecedents to the massive glass bead industry that later flooded the Atlantic world. Although Ife-inspired Venetian glass beads became a material symbol of the inequity of European relations with Indigenous populations, dichroic Ife beads could never be imitated. Unearthed accori beads continued to adorn the coastal elite along the Gulf of Guinea for centuries, and puzzled European scholars well into the 20th century.