In 1935, when the danger of a new war was becoming increasingly apparent, a committee was formed on 2nd August, to come up with a proposal for fortifications designed to provide strategic support for defensive operations. This ambitious task was to be carried out by the Forts’ Administration, Thessaloniki. The committee was headed by a Colonel of the Engineering Corps, Ioannis Strieber, and was called the Committee for the Study of Fortifications (EMO). Its remit was to decide on the most suitable form of fortifications to guard the zone, a general construction plan, a budget, and plan of works. Contributing to this project were: surveyors, geographers, engineers, architects, other military units such as the Engineers, and a number of agencies such as the National Metsovio Polytechnic, and many businesses in Athens and Piraeus (eg Gavalas, Triandaphyllides, etc). The military and civilians who participated were all the best in their fields.
Under considerable pressure of time, the Committee finalised its choice of construction sites for the forts and ancillary constructions, and submitted its report to the Ministry of Defence. After a period of consultation, a construction zone was decided on, which would stretch from Eastern Macedonia (Mt Beles) to Komotini, covering, section by section, a distance of 300km. This zone did not include the extension of anti-tank zones and additional fortifications which reached as far as the Evros.
The main purpose behind constructing this defensive line was not just for continual passive defence, but to repel a surprise enemy attack and simultaneously provide cover for military operations. The final study carried out by the Committee for the Study of Fortifications concerned itself with construction solely for the needs of guarding the border. It identified the following criteria:
1. The ability to immediately repel a surprise invasion.
2. Assured ease of recruitment from the population of the border region.
3. Assured speedy formation of a military force in the border region.
4. The securing of certain routes by the border guard for use by a military force.
The committee decided on the construction of enclosed defensive compounds with other constructions adjacent to them. They followed the example of the Maginot line, as the French army of the inter-war years was considered the most modern at that time. Groups of Greek officers visited the French defensive line and adopted some elements. However, most of the Greek defensive constructions were unique.
In 1936 the committee finished its deliberations on Forts Rupel, Karatas, Maliaga, Perithori, Lisse, and Pyramidoides, and the order was given to begin construction. Building began in Kerkine in 1936.
In the same year, Lieutenant General Alexandros Papagos was appointed head of Army General Staff, and made significant additions and changes to the plan. In May 1937, the KEO was at work in the border region north of Drama, and was exploring anti-tank placements between Forts Perithori and Lisse.
The building work was carried out by contractors between 1936 and 1938. Naturally, it was impossible for the work to be handled by the civil administration. Overall supervision was undertaken by an officer from the Engineering Corps, a veteran officer, or civil engineer and there were supervisors of various specialities, as well as soldiers with an officer to provide security.