The inscription was discovered in 1928, on the wall of a rock shelter near the village of Sitovo, close to Plovdiv, Bulgaria.
[1] In 1943, Peev was executed by firing squad on suspicion of sending a coded message to the Soviet Union.
He had sent an example of the text to Soviet archaeologists, in the hope that they could decipher its meaning.
[4] Peev was posthumously awarded the Order of Lenin for his resistance efforts against the Bulgarian government.
It has been variously identified as local ancient language, Celtic, Slavic, and Phrygian.