1 October – International Vexillology Day
October 1 is the International Day of Vexology. On that day in 1961 the first vexillological journal, Flag Bulletin, was published by Gerhard Grahl and Whitney Smith.
The picture shows a reconstruction of the Methodius’ flag when he governed the region around Strumica (845-855) from the Strumica Museum. This red flag with a golden cross before which he baptized Christians who had not yet been converted to Christianity. 
In the Eastern Roman Empire, flags were strongly influenced by the church in the Middle Ages, and the most common symbol was the cross. During the same period, during the reign of Macedonia by Boris (852-889) he sent a letter to Pope Nicholas I asking what flag to fly. In response, the Pope writes,there is no other flag besides the sign of the Holy Cross, explaining that Constantine the Great placed the cross on the red flag. This gives us guidance that most of the flags of that period were of the cross. 
 Бранко Панов, „за Методиевото словенско кнежество и создавањето на Закон судниуј Лудјам“, Зборник, Кирило-методиевскиот период и традициите во Македонија, МАНУ, Скопје 1988, 290.
 „Отговорите на папата Николай I към княз Борис“, Извори за Блгарската история, II, София,1960, 87-88.