Thanks to AI, we can play a Roman game again

For years a Roman stone found in Heerlen has kept people guessing: was it a game board or not? At last, scientific research carried out in Heerlen, Maastricht and Leiden delivers the answer. The stone is indeed a board game, and using 3D scans and AI, we know the rules.

A rectangle incised with diagonal and straight lines, hewn from limestone quarried in France, a thrilling strategy game can look deceptively simply. The Romans used glass, bone or earthenware pieces. Players took turns trying to block each other’s pieces; whoever did it in the least number of moves won.

What does the stone reveal?

“We can see wear along the lines on the stone, exactly where you would slide a piece,” says Walter Crist, an archaeologist at Leiden University who specialises in ancient games. “The appearance of the stone combined with this wear strongly suggests it’s a game.”

To get a clearer view of how the stone was used, Luk van Goor of restoration studio Restaura in Heerlen produced extremely detailed 3D scans. “Those scans reveal a lot of details of the lines, and they show that some of these lines are a fraction of a millimetre deeper than others. Those deeper lines were used more intensively. We also see that the stone’s edges are neatly finished, which indicates a final product rather than a piece awaiting further workmanship.”

The investigation went further by using artificial intelligence to look for possible rules. This work took place at Maastricht University and as part of the Digital Ludeme Project, which studied ancient games. Games are as old as humanity and tell us a lot about cultural development, yet they hardly survive. A rare exception is the Roman Mill Game. Being a yet unknown game makes the discovery of the nearly 2,000-year-old stone in Heerlen all the more remarkable.

Artificial intelligence

“We developed Ludii, a form of artificial intelligence that can deduce game rules,” says Dennis Soemers, a researcher in the Department of Advanced Computing Sciences at Maastricht University. “We trained Ludii with the rules of about a hundred mediaeval or older games from the same cultural area as the Roman stone. Ludii produced dozens of possible rule sets. It then played the game against itself and identified a few variants that are enjoyable for humans to play.”

Roman game stone with playing pieces dating to the Roman period in Heerlen
The Roman game stone found in Heerlen together with typical Roman game pieces.

The researchers then checked whether the movements of the pieces under those rule sets matched the wear visible on the Roman stone. Playing with a particular set of rules indeed produces the wear pattern seen in the 3D scans. Nevertheless, Soemers remains cautious about claiming the exact rules. “If you present Ludii with a line pattern like the one on the stone, it will always find game rules. Therefore, we cannot be sure that the Romans played it in precisely that way.”

So, a genuine game!

The researchers are confident that the stone indeed represents an ancient game, especially thanks to the new information from the 3D scans and the AI simulations. Karen Jeneson, curator of The Roman Museum in Heerlen comments, “We know the rules we found explain the wear marks on the stone and that they are consistent with games from comparable cultural periods. Of course we considered other possible uses for the stone, such as an architectural decorative feature, but we found no alternative explanation. So, the stone really is a board game. It’s no coincidence that Antiquity, one of the leading journals in archaeology, has published our research.”

The goal of the game is to lock in the pieces of the opponent. The oldest known variants of such games date back to the Middle Ages. The findings show that games of this kind were played centuries earlier than previously assumed.

The Roman game stone photographed on a table
The Roman game stone photographed on a table

Want to play the game yourself? Download it here!

The scientific article on the Roman Game can be found at: link to follow

The research was part of the now completed Digital Ludeme Project, which used artificial intelligence to produce more reliable reconstructions of ancient games that are plausible both historically and mathematically.

The study was conducted by researchers from the universities of Maastricht, Leiden, Louvain-la-Neuve and Adelaide, The Roman Museum and restoration studio Restaura in Heerlen.

Author: Patrick Marx

Photography: Het Romeins Museum

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