The icon “St. Theodore Stratelate” has a special place in the Bulgarian history and is emblematic for Bulgarian Christianity. Saint Theodore Stratelate was a patron saint of the First Bulgarian capital city – Veliki Preslav. The icon dates back to the 9th-10th centuries and is a masterpiece of the Preslav Ceramic School. Discovered during the earliest archaeological investigations of the site of Veliki Preslav, the numerous fragments of broken white-clay ceramic tiles that currently form the image of the saint were assembled in the beginning of the 20th century. Later on, many conservation interventions on the icon were introduced, aiming to stabilize its state due to the numerous presentations of the icon beyond the Bulgarian borders. Currently, the icon is exhibited in the National Archaeological Museum. The new restoration treatment of the icon aims at removing all conservation materials introduced during previous interventions; a scientific investigation of the icon, including determination of the chemical profile of the ceramic tiles, as well as identification of decorative techniques; consolidation and stabilization of highly fragile original materials; and reinstating of the icon’s aesthetical value.