A 2,000-year-old ritual bath has been discovered with an encoded message written on the side in symbols and inscriptions. Archaeologists found the mystery message during a routine inspection at a construction site of a nursery school in the Arnona quarter in Jerusalem.

Experts from the Israel Antiquities Authority (IAA) said that during the excavation, they came across an "impressive ritual bath" – known as a miqwe – dating to the Second Temple (538 BC to 70 AD). "The walls of the miqwe were treated with ancient plaster and were adorned with numerous wall paintings and inscriptions, written in mud, soot and incising," a statement said.

encoded message ritual bath Jerusalem
Experts do not know the meaning of the message or who left it IAA

"The inscriptions are Aramaic and written in cursive Hebrew script, which was customary at the end of the Second Temple period. Among the symbols that are drawn are a boat, palm trees and various plant species, and possibly even a menorah."

Excavation directors Royee Greenwald and Alexander Wiegmann said it is a "very significant discovery", and that the state of preservation was rare, unique and "most intriguing". The archaeologists say the inscriptions are a mystery, but some could indicate names. Symbols depicted are common to the Second Temple period. "On the one hand the symbols can be interpreted as secular, and on the other as symbols of religious significance and deep spirituality," Greenwald and Wiegmann said.

encoded message ritual bath Jerusalem
The inscriptions are so fragile they had to be removed from the cave immediately IAA

The paintings are extremely sensitive and exposure to the air causes damage to them, so experts removed them from the ritual bath immediately and transferred them to conservation laboratories for treatment and stabilisation.

The team now hopes to work out the relationship between the symbols and inscriptions and why they were drawn on the ritual bath. The IAA said: "Who is responsible for painting them? Was it one person or several people? Was it someone who jokingly wanted to scribble graffiti, or perhaps what we have here is a desire to convey a deeply spiritual and religious message, perhaps even a cry for help as a result of a traumatic event?"

encoded message ritual bath Jerusalem
The room where the ritual bath was found IAA

Moshe Tur-Paz, head of the Education Administration at the Jerusalem Municipality, added: "The archaeological and historical site that was exposed is of tremendous value to our identity as a Jewish people which might shine more light on the lives of our ancestors in the city of Jerusalem. We will maintain contact with the Israel Antiquities Authority and together we will examine how we can give educational and symbolic expression to the discovery that was found."