From 1821, when the Greek Revolution broke out, until the National Assembly of Epidaurus in 1822, there was no unified administration of the struggle. So each military corps had its own flag.
The revolutionary flags were in the colors of Filiki Etaireia (white-black-red), and its symbols (such as an anchor or a palm tree). Others followed the chariots of the charioteers, which had the cross and a saint on them, while some others rebelled under the banner of their parish church.
On January 13, 1822, which, in addition to the "Provisional Government of Greece" and its first constitution, also voted for the shape of the Greek flag. The colors that were established were blue and white. After the colors were decided, it was left to the Executive Body to determine what its final form would be.
According to theories that have circulated in the years since, the National Assembly rejected red and green, colors directly associated with the Ottoman Empire. The choice of blue and white, on the other hand, symbolize the blue color of the Aegean sea and the white of its waves.
Another theory, better known and more widespread than the previous ones, concerns the stripes, which symbolize the syllables of the phrase "liberty or death", the five blue ones the syllables "E-leu-the-ri-a" and the four white ones "or Tha-na-tos".
Two months later on March 15, 1822, the final decision of the Executive Body was issued, which was signed by Alexandros Mavrokordatos. The decree stated:
a) of the land forces, the square-shaped flag would have a blue area, which would be divided into four equal parts from edge to edge of the area
b) the maritime flag would be double, one for warships and another for commercial ships. And for the warships, the area would be divided into nine horizontal parallelograms, with the colors white and blue remaining in them, and in the upper inner corner of this area, a blue square was formed, divided in the middle by a white cross. And the area divided by the merchant ships would be blue. In the upper inward corner of this area, a white square was also formed and divided in the middle by a blue cross.
The flag of the land forces was the official flag of the Greek state until 1978. Today, the "flag at sea" of warships has prevailed as the official symbol of the Greek nation.
Source: EDaily