The "Hymn to Liberty", or "Hymn to Freedom", is a poem written by Dionysios Solomos in 1823 that consists of 158 stanzas and is used as the national anthem of Greece and Cyprus.
The anthem was set to music by Nikolaos Chalikiopoulos Mantzaros in 1865 and is the longest national anthem in the world by length of text. It officially became the national anthem of Greece in 1865 and Cyprus in 1966.
The hymn was inspired by the Greek War of Independence. The hymn was written by Solomos in order to honor the Greeks’ fight for independence throughout the years of Ottoman rule. "Hymn to Liberty" recounts the misery of the Greeks under the Ottomans and their hope for freedom. He describes different events of the War, such as the execution of Patriarch Gregory V of Constantinople, the reaction of the Great Powers, extensively the Siege of Tripolitsa and the Christian character of the struggle.
This national anthem has been played at every Olympics closing ceremony in order to honor Greece’s role as the birthplace of the Olympic Games.
According to Wikipedia