AEP Iraklis

Foundation and first years (1899–1912)

G.S. Iraklis Thessalonikis traced its roots back on 1 July 1899 when Omilos Filomouson (Greek: Όμιλος Φιλομούσων, lit. 'Muses Friends Group') was established. The club was established as a cultural union of the Greeks of Thessaloniki (then under Ottoman sovereignty), and its sports department was founded in 1902. In 1903 the club joined forces with Olympia, another greek Gymnastic Club of Thessaloniki. Football was a new sport at the time, but rapidly increasing in popularity and thus the board of directors decided to line up a football team. The first football match that was held on 23 April 1905 by the Omilos Filomouson football team which won by 3–0 against Union Sportive, team of the Western European diaspora of Thessaloniki.

Later on, Omilos Filomouson faced financial problems. As a result, members of Omilos Filomouson founded on 29 November 1908 a new sporting club, called Makedonikos Gymnastikos Syllogos (Greek: Μακεδονικός Γυμναστικός Σύλλογος, lit. 'Macedonian Gymnastic Club'), that gained a permission to operate by the Ottoman authorities. The new club's first president was a Greek doctor, Alkiviadis Maltos. The name of the club had a direct reference to the ethnic tensions that took place in the area at that time.

Due to the Young Turks revolt of 1908 and their promises for ease of ethnic tensions in the area, the club was forced to change its name. Thus a new name was decided in 1910 for the club, Othomanikos Ellinikos Gymnastikos Syllogos Thessalonikis "Iraklis" (Greek: Οθωμανικός Ελληνικός Γυμναστικός Σύλλογος Θεσσαλονίκης «Ηρακλής», lit. 'Thessaloniki Ottoman Greek Gymnastic Club "Heracles"'). Τhe name "Iraklís" (Greek: Ηρακλής, lit. 'Heracles') was added to the club's name as an honour to the ancient Greek demigod. The new name was approved, together with a new statute and a new board of directors, by a general assembly of the club on 13 April 1911.

National establishment and early success (1912–1959)

After the integration of Thessaloniki in the Kingdom of Greece on 26 October 1912, the operation of the club was accepted by the Greek courts in 1914 and became a fully registered sports club on 11 January 1915 as Gymnastikos Syllogos Thessalonikis "Iraklis" (Greek: Γυμναστικός Σύλλογος Θεσσαλονίκης «Ηρακλής», lit. 'Thessaloniki Gymnastic Club "Heracles"').

Shortly after the end of the Second Balkan War, Iraklis together with the 3 Jewish football clubs of the city, Progrès Sportive, Alliance and French-German School Alumni Union organised the first Thessaloniki Football Championship in January and February 1914. Iraklis won Alliance 3–1, Progrès Sportive 5–1 and after winning the French-German School Alumni Union, the club was proclaimed Champion of Thessaloniki. On 6 April 1914, Iraklis Thessaloniki played a match against Athinaikos Syllogos Podosferiseos, that ended as a draw. It was the club's first match against a club outside Thessaloniki. In 1914, Iraklis established the club's youth squad, so the students of the Greek Gymnasium of the city could train in football. A year later Iraklis won the second Thessaloniki Football Championship. The next championship was not held due to World War I.

In the years following World War I, several football clubs were established in Thessaloniki and that led to the establishment of the Macedonia Football Clubs Association in 1923. The first championship from the newly founded association was organised shortly afterwards and Iraklis lost in the tournament's final 4–1 to Aris. In 1924 Iraklis played its first match against a club from outside the borders of Greece. It was a match against Yugoslav club SSK Skopje, a contest that ended 2–1 in favour of Iraklis. It was in that same year that Iraklis played its first match abroad, a 3–0 friendly win against SK Bitola. In 1926 the club appointed Hungarian József Schweng as manager, the first ever foreign manager in Greece. Under Schweng's guidance, Iraklis won the Championship organised by the Macedonia Football Clubs Association in 1926–27. By winning 6–0 against the reigning champion of Western Macedonia Ermis Sorovič and the champion of Eastern Macedonia and Thrace Rodopi, Iraklis was proclaimed Champion of Macedonia and Thrace. In the following years, Iraklis did not have any success, finishing in runner up and even lower positions in the Macedonia Football Clubs Association Championship.

In the 1933–34 season Iraklis won the North Group of the Panhellenic Championship qualifying for the championship final, where the club had to compete against the champion of the South group Olympiacos. The first leg was played in Iraklis Ground on 10 June 1934. Although Iraklis took a 2–0 lead at half time, Olympiacos managed to make a comeback in the second half, winning the game by a 2–3 scoreline. The second leg was played a week later in Piraeus and Olympiacos was proclaimed National champion by winning this match 2–1.