The version of the monument of mid-4th century BC (so-called Period I) therefore included ten statues, one for each hero designating a phyle.

[8] While not immediately identified (for tens of years the researchers referred to it as "Periphragma" or "Fenced Peribolos",[2] the original report simply stated that this was not the Stoa of the Herms[8]), the importance of the monument was clear due to its large size (the length of the fenced area was over 21 m (23 yd) long at the maximum, apparently during Period V[9]), location next to Bouleuterion, and openness to the center of the Agora.

Instead, as the archeologists understood the layout of agora better and better, the fact that "peribolos" represent the ruins of the Monument of the Eponymous Heroes became "increasingly clear".

[2] T. Leslie Shear, Jr. [de] attributes the first detailed explanation of the identification to the 1949 article[10] by Eugene Vanderpool, where the author, among other considerations, had dealt with the remark by Pausanias that the monument was located above the Tholos (No.

Vanderpool also explains the words of an unknown commenter of Aristophanes' Peace that the monument was close to Prytaneion (Pausanius places the latter on the northern slope of the Acropolis).

[11][8] The monument was the first major discovery of the first archeological season in 1931, with a detailed study of the foundation of the still unidentified structure published in 1933 by Richard Stillwell [de].

[2] The monument was placed almost parallel to the porch of the Bouleuterion, on the east side a major road that formed the eastern boundary of the market area of the Agora.

[12] Only the north end of the sill has any semblance of a foundation, while the rest was placed onto a shallow layer of earth spread across the rough surface packed by the previous intensive traffic.

[16] Very little is left from the superstructure of the monument, though enough to permit a reconstruction:[17] Periods II and III, with their additions of statues, required a redesign of the pedestal.

At the same time, the fence construction on the eastern (apparently, more important) side, previously made of poros stone, was replaced by one of Pentelic marble, taller, but of "rather poor quality."

[21] After the Cleisthenes reform, each Athenian phyle was no longer an actual kinship group,[22] but more of an administrative subdivision, symbolically designated by an eponymous "founder", originally a legendary hero, later an honorary figure.