The founder of the Company ELLINIKA TECHNIKA ERGA S.A. is Mr. Periklis Triantafyllidis, a Chartered Civil Engineer of NTUA (National Technical University of Athens) who entered the construction sector in 1923, as Head of the Technical Bureau PERIKLIS TRIANTAFYLLIDIS and Co. – GENERAL CONTRACTING with a great number of diverse works, that are still operational both locally in Athens and nationally in Greece.

In 1950, the sole proprietorship changed its legal form and became a Societe Anonyme (S.A.) operating under the name ELLINIKA TECHNIKA ERGA S.A. Mr. Periklis Triantafyllidis, the founder of the Company, was appointed as the first President of the Board of Directors.

1923-1940

Successful participation in the full range of Public and Private works in Greece.

• Underground fortification works of the Northern Line of Defense at Forts Lisse – Dasavli – Pyramodoeides at the Greek – Bulgarian borders.
• Coastal defense fortification works in the islands of Evia and Aegina.
• Building works including part of the Army Pension Fund Building ("Metochiko Tamio Stratou") in the centre of Athens (Voucourestiou and Stadiou Str).
• Restoration of the Bank of Athens building (now secondary headquarters of the National Bank), Klathmonos Square.
• Former Athens Court of First Instance (Stadiou – Santaroza – Har. Trikoupi) for which Mr. Triantafyllidis received a congratulating letter by the Prime Minister Eleftherios Venizelos.
• Various buildings and condominiums (5 Lycabettus Str, 28 Tsakalof Str, etc.)

1940-1950

Greece's entry into World War II in October 1940 was followed by a period of inactivity because of the enlistment of all male staff, including Mr. Periklis Triantafyllidis, and the requisition of all technical equipment and transportation means by the Army.

The world war and the subsequent civil war left the company in tatters. It was not before 1950 that the company managed to recover.

1950-1995

The new Societe Anonyme "ELLINIKA TECHNIKA ERGA S.A." is awarded a "...special certificate Ε' to participate in bidding for reconstruction works...." and participates in the construction of large projects:

• Reconstruction of National Road Korinthos – Argos – Tripoli and National Road Argos – Nafplio using equipment granted under the Marshall Plan by the United States.
• Large-scale diverse ground and underground projects for the Greek Army, Navy and Air Force.
• Road construction works, for example, sections of the motorway now known as EGNATIA ODOS between Komotini and Alexandroupoli, Alexandroupoli and the Airport, grade-separated interchange in Koukaki, etc.
• Major building works, for example, the entire building block of the American College for Girls (Pierce College) in Agia Paraskevi, part of the nitrogenous fertilizers plant in Ptolemaida, the Kefalonia General Hospital "AGIOS GERASIMOS" in Argostoli, two distribution centers for PPC S.A. (Public Electricity Company, DΕΗ) in Athens (Aristeidou Str) and Piraeus (Ag. Dionysus Str), etc.
• Sports centers, for example, the Athens College Indoor Sports Centre (Palaio Psychiko), the German School of Athens Indoor Swimming Pool.

1995

In the summer of 1995, ELLINIKA TECHNIKA ERGA S.A. merged with THEMELI S.A. to become part of the extended Company.