What is flag of the byzantine empire?

The flag of the Byzantine Empire, also known as the Palaiologos dynasty flag, features a black double-headed eagle on a gold background. The eagle is said to represent the power and dominion of the Byzantine Emperors over both the East and the West. It was also believed to symbolize the unity between the secular and religious aspects of the Byzantine state, with one head of the eagle looking towards the East (representing the secular power) and the other head looking towards the West (representing the religious power). The double-headed eagle has remained a significant symbol for many countries that were once part of the Byzantine Empire, including Greece and Montenegro.