A Greek text inscription on a rock in Delphi Teefa/Getty Images

Artificial intelligence is learning to decipher damaged ancient Greek engravings. The AI seems to be better than humans at filling in missing words, but may be most useful as a collaborative tool, where researchers use it to narrow down the options.

There are thousands of ancient inscriptions we already know about, with dozens more discovered every year. Unfortunately, many have become eroded or damaged over the centuries, resulting in segments of text being lost. Figuring out what the gaps could be is a difficult task, involving looking at the rest of the inscription and other similar texts.

Yannis Assael at DeepMind and his colleagues trained a neural network, a type of AI algorithm, to guess missing words or characters from Greek inscriptions, on surfaces including stone, ceramic and metal, that were between 1500 and 2600 years old.


The AI, called Pythia, learned to recognise patterns in 35,000 relics, containing more than 3 million words. The patterns it picks up on include the context in which different words appear, the grammar, and also the shape and layout of the inscriptions.

Given an inscription with missing information, Pythia provides 20 different suggestions that could plug the gap, with the idea that someone could then select the best one using their own judgement and subject knowledge. “It’s all about how we can help the experts,” says Assael.

To test the system, the team hid nine letters of a Greek personal name from Pythia. It managed to fill in the blanks. In a head-to-head test, where the AI attempted to fill the gaps in 2949 damaged inscriptions, human experts made 30 per cent more mistakes than the AI. Whereas the experts took 2 hours to get through 50 inscriptions, Pythia gave its guesses for the entire cohort in seconds.

This shows the potential of AI-assisted restoration, says Thea Sommerschield at the University of Oxford, who was part of the team. “The reward is huge because it tells us about almost every aspect of the religion, social and economic life of the ancient world,” she says.

Philippa Steele at the University of Cambridge agrees that Pythia could assist restoration efforts, although humans would still be needed to put the pieces together by eye and then decipher them before this could happen.

“It looks to me as though the highest success rates would be achieved when… we are just missing small parts of a long text, or when there are plenty of similar parallels for a newly discovered fragmentary text,” she says.

Reference: arXiv, arxiv.org/abs/1910.06262