A new stamp series celebrating outstanding Ancient Greek literary and philosophical figures was issued by the Hellenic Post Office (ELTA) on March 15, the service said.

In an announcement on the series, ELTA said, "In order for a tree to bear fruit, it must first spread its roots, grow a trunk and develop fully; and that usually takes time," referring to the emergence of the fields of history, tragedy and philosophy that honor Herodotus, Euripides, Xenophon, Socrates and Epicurus.

Likening the emergence of the 5th and 4th century historians, authors and philosophers to a "bolt of lightning ripping through the clear air at the start of a storm," the post office said that "Greek thought, having already shown its worth through trials and tribulations, has now become aware of its strength and is unhesitating in showing it off, no less thunderously than exuberantly."

"The 5th and 4th centuries are unique in the history of the human thinking, in the excessiveness and plurality in which they appear: Never before and never since, have so many exemplary minds congregated, in the same city and at roughly the same time; in Athens, the centre of the known world: Herodotus, Euripides, Xenophon, Socrates and, shortly after, Epicurus," ELTA added.

The series were based on designs by Yannis Gourzis and are available in packs of 100 stamps, perforated on one side and cut on the other. The remainder is printed on fully perforated sheets of 25 stamps. First-day covers and set albums will also be available at Hellenic Post Offices, all until sold out.