On July 27th the Bulgarian Orthodox Church honors Saints Cyril and Methodios with five of their most famous disciples - Clement, Nahum, Sava, Gorazd and Angelarius. Though these Saints each have their own feast day, today they are celebrated together.
After the death of Cyril and Methodios in Moravia, some of their disciples fled persecution and arrived in Bulgaria, where they found refuge and support, while others were sold to Jews as slaves and taken to Venice where they were bought by ambassadors of the Roman Emperor Basil the Macedonian and returned to Constantinople. Clement and his companions were forced to march to the border, being beaten all along the way by German soldiers. All this was done secretly without the knowledge of King Wiching, who had wished, in his stubborn and obstinate heretical belief, to keep them in prison and to continue tormenting them until they recanted their faith.
It was Clement and Nahum who led the missionary activity in Bulgaria. Angelarius had received such grievous wounds that he reposed in the Lord soon after returning to Bulgaria. We do not know what happened to Sava and Gorazd.
The Bulgarian king Boris I welcomed them, giving them encouragement and state support for their sacred work. There were two main educational centers with training schools and scriptoria for translating from Greek into Old Slavonic Christian literature and its dissemination, but also to prepare priests for the young Bulgarian Christian Church.
Nahum was head of the school in Pliska, which was moved to Preslav in 893 and became known as the Preslav Literary School. In 886 Clement was sent to establish a school in the southwestern Bulgarian land of Ochrid (Ochrid Literary School), and even local administrative and military authorities were put in his submission. We are told that over seven years he personally trained over 3,500 priests and teachers. He was joined with Nahum in 893.
Thus, for after a short time the Greek language in the liturgy and the administration was replaced with the local Bulgarian language understood by virtually the entire population in the Bulgarian lands.