Flag of Greece ensign Greek Orthodox merchants (better: merchants from the Greek-dominated Orthodox "millet") were allowed to fly on their ships, combining stripes with red (for the Ottoman Empire) and blue (for Orthodoxy) colours. After the Treaty of Küçük Kaynarca, Greek-owned merchant ships could also fly the Russian flag. During the uprising of 1769 the historic blue cross on white field was used again by key military leaders who used it all the way to the revolution of 1821. It became the most popular Revolution flag, and it was argued that it should become the national flag. The "reverse" arrangement, white cross on
Flag of the Greek Orthodox Church of the Byzantine Empire. The double-headed eagle was historically used as an emblem in the late Byzantine period (14th–15th centuries), but not on flags; rather it was embroidered on imperial clothing and accoutrements by both the Palaiologos emperors of the Byzantine Empire and the Grand Komnenos rulers of the Empire of Trebizond, descendants of the Byzantine imperial family of the same name. The actual flag of the Palaiologan-era Byzantine Empire was based on the tetragrammatic cross in gold on a red background. This design also forms the basis for another flag used by the Orthodox Church of Greece, with the