According to prominent Bulgarian archaeologist Nikolay Ovcharov, the inscription was made by the monk Antoniy in 921, who had most likely founded the monastery, Darik radio reports.

Prior to this discovery, the oldest preserved Cyrillic inscription was identified as being the one found in the former Bulgarian capital of Veliki Preslav by Prof. Dimitar Ovcharov. The inscription, which read “Altsek” and the year 931, had been found on a ceramic vessel in Bulgaria's medieval capital.

The reading of the inscription discovered at the rock monastery near Krepcha has been entrusted to Prof. Kazimir Popkonstantinov of Veliko Tarnovo University. A liturgy was delivered at the rock monastery for the first time in 1100 years on Thursday by priest Serafim. 

Source: Novinite