Who were the first kings of Europe? Homer heroes such as Agamemnon are the first to pop up in the minds of educated Westerners, but hierarchical societies on the continent predate the ancient Greeks. Millennia before them, people in southeastern Europe went on the long and often tortuous transition from simple farming communities to complex political organisations.

An exhibition tells their story to audiences in the United States and Canada, unveiling a world of history, discovery and fascination. Organised by the Field Museum and scheduled to open in New York City, Chicago and Gatineau, Canada, The First Kings of Europe features finds lent by some of the finest museums in Bulgaria, Albania, Croatia, Hungary, North Macedonia, Romania, Serbia and others. These artefacts reveal the life, power and religions in prehistoric Europe between the end of the last Ice Age and the 1st millennium BC, and are as beautiful as they are scientifically important: elegant and mysterious pottery and ceramic objects, elaborate pieces of jewellery and impressive weapons, and tools of copper and bronze.

A feast is depicted on the vessels from the Borovo Treasure in the Ruse Regional History Museum

Some of the exhibition's centrepieces come from Bulgaria, which lies on an ancient crossroads since the first farmers' arrived from the Middle East. The Bulgarian finds come from the collections of the National History Museum, the Ruse Regional History Museum and the Varna Archaeology Museum, and were included in the exhibition with the support of the America for Bulgaria Foundation.

Gold clothes ornaments, pieces of jewellery, a staff and a suspected penis sheath: the finds from the Varna Chalcolithic necropolis, which date back to 5000 BC, are unparalleled in their historical significance. Made by a community that already knew how to make tools and weapons of copper, they are the earliest gold objects known to science worldwide. Their importance goes even further. The gold items were buried, along with other precious objects such as fine flint tools, lavishly decorated pottery and sea shells imported from the Mediterranean, in just a couple of graves in a large necropolis. This is a clear sign of social stratification, one of the earliest indicators that simple farming communities of the Neolithic had given way to more hierarchical societies.

Bull-shaped clothes ornaments of gold, discovered in an empty, probably symbolic, grave in the Varna Chalcolithic Necropolis. The necropolis finds are the centrepiece of the Varna Archaeology Museum. Photography by Ádám Vágó © Field Museum

Who were the people at the top of the social pyramid? Were they kings? Or priests? Or both? How did they manage to stay in power?

Historians and archaeologists still struggle to find the answer. Social change in prehistoric southeastern Europe could have been provoked by mastering copper production. People, who were able to turn seemingly insignificant pieces of rock into hot metal and then into effective tools and weapons, might have appeared to the laity as magicians or masters of divine faculties, thus amassing political power as well. Another factor could have been the widening of preexisting long-distance trade routes and the introduction of organised trade with valuable commodities such as salt.

A rhyton, or horn-like drinking vessel, from the Borovo Treasure. Ruse Regional History Museum. Photography by Ádám Vágó © Field Museum

Social transformation in prehistoric southeastern Europe continued further when the region entered into the Bronze Age. This was an era of new and better tools and weapons of a more effective metal, the introduction of horses as combatant animals and a supposedly violent change of populations and even of religions from more feminine to a more masculine pantheon. All of these led to even more complex societies: people organised to survive in a changing environment with increased danger of war.

Eventually, in the 2nd millennium BC, in the lands of what is now Bulgaria, a people whose name we know from historical sources emerged. These were the Thracians. In the 1st millennium BC they created kingdoms, built fortresses and tombs, and made history. The Thracians persisted in the region for centuries. They adapted to the Roman conquest until, in the 7th century AD, they were incorporated in the then young Bulgarian state. But before then, in the 1st millennium BC, they were an important political actor. The Persian invasion in the late 6th century BC galvanised the Thracian tribes into creating the first historically documented kingdoms in the region. These remained a fixture in southeastern Europe until the Romans' arrival.

The Thracian kingdoms were ruled by a powerful elite of kings, noblemen and their armies. The objects from the grave of a mid-4th century BC Thracian nobleman, excavated by the modern villages Malomirovo and Zlatinitsa, featured in the First Kings of Europe, present a coherent picture of the lifestyle and beliefs of the Thracian elite.

The man was just 18-20 years old when he died and was buried as befitting for a Thracian noble – in a tumulus, along with expensive items and slaughtered dogs and horses. As he was a warrior, a classical bowed Thracian sword, 177 bronze arrows, seven spears, a knitted breastplate and a helmet decorated with a three-headed snake accompanied him in his grave. The silver greave with gilt and decoration of a human face is more enigmatic – it would be impractical to use in a real battle, and the other part of the pair is missing. The other luxury items buried with the man reveal the deceased's lifestyle and religious beliefs – a beautiful gold wreath, a gold ring picturing himself receiving immortality from the Great Goddess, and a set of silver and gilt drinking vessels.

The silver greave from the Zlatinitsa-Malomirovo grave, from the collection of the National History Museum, was a part of the exhibition at the Institute for the Study of the Ancient World in New York City

Drinking also defines another impressive find representing the ancient Thracians in the First Kings of Europe exhibition. The Borovo Treasure was discovered accidentally near Ruse and consists of vessels that initially belonged to different sets, made between the late 5th and the late 4th century: three rhytons, or horn-like vessels, a vessel combining the shape of a rhyton and a jug, and a krater, or a deep bowl with two handles for mixing of wine and water. The treasure was possibly used in rituals devoted to Dionysus or the Cabeiri, the Thracian deities of sea, fertility, fire and metallurgy.

The rhytons were probably made at a workshop specialising in such craft in the northwestern part of Asia Minor. The name, in Greek, of the Thracian king Cotys is written on two of them. The krater is adorned with a scene of a gryphon attacking a doe, its style suggests that it was made by a Thracian artisan.

Two rhytons from the Borovo Treasure, exhibited in NYC. The treasure is kept at Ruse Regional History Museum

According to a hypothesis, the treasure was a gift by King Cotys, who ruled south of the Stara Planina mountain range, to an anonymous Thracian king whose realm was north. Why and when it was buried remains a mystery. It could have been hidden in turbulent times, but religious activity is another possible explanation. Thracian kings used to bury precious items as a way to appease the gods or to declare their ownership on their lands.

The gold earring with a delicate depiction of Goddess Nike on a chariot, discovered in a funeral mound near Sinemorets, at the Black Sea coast, is also related to religion. According to archaeologists, the grave possibly belonged to a priestess.

Gold earring with the Goddess Nike found in a grave near Sinemorets, from the collection of the National History Museum. Photography by Ádám Vágó © Field Museum

The First Kings of Europe tells a fascinating story and presents a rare opportunity to introduce a little known culture to an overseas audience. The New York City show is already open for visitors, at the Institute for the Study of the Ancient World, until February 2023. On 31 March, The First Kings of Europe will open at Chicago's Field Museum where it will stay until the end of January 2024. From April 2024 to January 2025, the exhibition will be at the Canadian Museum of History Gatineau, QC, Canada.