The national flag of Greece has nine alternating blue and white horizontal stripes. In the upper, left-hand corner is a blue canton bearing a white cross, which symbolises Eastern Orthodox Christianity.

According to tradition, the nine stripes represent the nine syllables of the Greek for "Freedom or Death" (Ελευθερία ή Θάνατος). Others claim the nine stripes represent the letters of the Greek word for "freedom" (ελευθερία).

A third story suggests the nine stripes symbolise the nine Muses, the goddesses of art and civilisation: Calliope (epic poetry), Clio (history), Euterpe (flutes and music), Thalia (comedy and pastoral poetry), Melpomene (tragedy), Terpsichore (dance), Erato (love poetry and lyric poetry), Polyhymnia (sacred poetry), and Urania (astronomy). As for the colours, white and blue may symbolise the colours of the sky and sea.

The Greek flag allegedly derives from the coat of arms of the Kallergis family who were once the mightiest noblemen of Crête (17th century). The family claimed to be the ancestors of Byzantine Emperor Nicephorus II Phocas (963–969 AD).

Initially, the Greek flag only consisted of a white cross on a blue background, which was recognised as the country's official flag in 1822. The nine stripes were added later but were not made official until 1978.

More Info: en.m.wikipedia.org