The Dispilio tablet is a wooden tablet bearing inscribed markings, unearthed during George Hourmouziadis's excavations of Dispilio in Greece, and carbon 14-dated to 5202 (± 123) BC. It was discovered in 1993 in a Neolithic lakeshore settlement that occupied an artificial island near the modern village of Dispilio on Lake Kastoria in Kastoria, Western Macedonia, Greece.

Source Wikipedia

The cedar tablet is carved with ten rows of linear (vertical and horizontal) signs. The symbols, which have also been found on clay tablets from the same area, have not yet been deciphered.

Further details (with photos) : Radiocarbon Vol 56, No 2, 2014, p 511–528