Travellers during the late Ice Age would pick up an etched horse jawbone as a souvenir of their time in Europe.
Arriving in Wales they would then display the trinket in their cave as a memento of their time abroad.
And now experts believe this 11,500BC example is the“oldest ever piece of Welsh artwork”.
With an intricate zig-zag pattern the keepsake could also signal an important evolutionary step in communication, they said yesterday – like a postcard, diary or a letter.
It was originally unearthed with the remains of four ancient individuals in 19th century excavations of Thomas Kendrick’s Cave, Llandudno.
But new research by scientists at the British Museum, plus Oxford and Bradford universities shows the piece is far older than first thought.
Jill Cook, Deputy Keeper of Prehistory and Early Europe at the British Museum, said, “The decorated fragment of a horse jaw that was discovered in Kendrick’s Cave is the oldest known work of art from Wales that I know of.
“We have discovered that it is 13,500 years old – around 10,000 years older than first thought.
“The use of the horse’s chin and the blocks of zigzag patterns make it rare and unusual in Europe at this time.
“I cannot put a value on it. Such objects are so precious and archaeologically priceless, that they simply don’t come on the market so there is nothing to compare with.”
The cave and its archaeology reveal the life of a family of hunter gatherers at the north western edge of the late Ice Age Europe they roamed. The bones found are those of three adults and one teenager, who are likely to have travelled through France and Belgium to reach their final resting place.
Ms Cooper said, “We are what we eat in a fundamental way and the different foods we eat have a particular isotopic signal which is left in our bones.
“We have discovered that these were a robust people who were used to walking long distances.
“They possibly migrated here from other parts of Europe, such as France and Belgium, where decorated bear teeth have also been found.
“And they would probably have brought the decorated horse’s jaw and bear teeth with them from their homeland, to their new life, to pass on through the generations, a bit like a grandmother’s scarf.”
To the untrained eye the zig-zags look like doodles. But Niall Sharples, from Cardiff University’s School of History and Archaeology, said the intricate designs were probably an early form of communication that marked a step forward in evolution.
He said, “They show there was a need to communicate complex ideas that make us who we are.
“Visual communication and the need to speak are closely related. The drawings and decorations demonstrate the sudden development of a more complex brain that had evolved from the Neanderthals. These people wanted to convey complex ideas, to create bonds among people and to organise them into groups and schedule actions.
“I have seen more complex spirals in stones from the entrance of a tomb in Orkney from a later period of about 5,000 years ago.
“But such objects are very rare in Britain because we do not have deposits that are as well preserved as they are in France or other parts of Europe.
“That’s why the Welsh caves and the material found within them are so important.”
Finds from Kendrick’s Cave will be reunited for the first time in 100 years with the opening of the Sharing Treasures exhibition at Llandudno Museum, on April 1.
The items will be on loan from the National Museum Wales and the British Museum.