The Day of Saint Brothers Cyril and Methodius is May 24
On May 24 Bulgaria marks the Day Of Slavonic Alphabet, Bulgarian Enlightenment and Culture. It has been celebrated since May 11, 1851 (old style).
Brothers Cyril and Methodius – the creators of Slavonic Alphabet, had been saints since the 9th century, and the commemoration of their day had been celebrated since the 12th century.
The first commemoration of the date had been initiated by Nayden Gerov. It was held in Plovdiv on 11 May 1851, although an Armenian traveler mentioned his visit to the “celebration of the Bulgarian script” in the town of Shumen on 22 May 1803.
May 24 is an official holiday of Bulgaria since 1990.