Since there is a bit of slience lately regarding Amphipolis, I thought it may be interesting to bring to your attention a monument that has the closest resemblance to the Kastas monument. It is located at Archontiko, near Pella, and its termed as a "heroon". Some basic facts:
a) It is a tumulus with a round wall (peribolos) that has a perimeter of 158.5 meters. The diameter (not perimeter) of Kastas is 158.4 meters
b) The peribolos is decorated with shields. Shields have been found in the scattered peribolos piecies of Kastas, near the lion, although they are currently attributed to the lion's base.
c) In the east side they found a dromos that leads to a double chambered macedonian tomb. The dromos for the entrance to the tomb had a downhill slope - according to the excavators that was rather unusual and at the time of discovery only a tomb at Pydna is referred as having similar characteristics.
d) This tomb/heroon was never completed, despite the effort and money spent for it. According to the excavators construction was probably interrupted due to the unstable situation in the region during the early period of the Antigonid dynasty - Pyrrhus/Gauls may have had some influence on that.
e) The partial completion of the tomb and tumulus allows researchers to understand the construction process of such large scale monuments. I assume that may be useful for studying the Kastas tumulus.
f) Based on ceramics, the construction is dated in the reign of Antigonus Gonatas or slightly earlier.
g) For static and/or financial reasons, the heroon was built - in part - on the site of a natural hill. The tumulus was not fully artificial, same as at Kastas.
h) The measurement unit (emvates?) for the heroon was determined to be 0.328 meters. Published studies of the Kastas blocks near the current location of the Amphipolis lion give a similar result. Bakalakes (1932) gives also 0.328 meters, Miller gives 0.325 meters with some margin that allows agreement of all measurements. The excavators of the heroon state that this value corresponds to a doric foot.
i) The shields of the heroon have a diameter of 0.62 meters, the excavators state that is typical for the shields of phalagites. They think, based on that, that the tomb may have been intended for a commander of such a unit.
j) No marble was used, only limestone.
I assume that if Gonatas did not bother to complete this monument after he kicked out Pyrrhus and the Gauls, he would have never bothered to construct and complete a much more expensive and grand monument at Kastas, so maybe its logical to assume that the Kastas tomb predates that heroon. The heroon construction may have been influenced by the Kastas monument.
One may find the presentation of the results from the proceedings of the yearly Archaeological excavations in Macedonia and Thrace meeting, taking place since 1987. The proceedings are freely available, except those of the latest years. They are, of course, in Greek, abstracts may be found in English. They are many interesting things to read in there.
http://aemth.gr/el/praktika
Initial results about the heroon are in the 1st proceedings series (1987), some photos from the article are attached below.
Another photo is here:
http://www.pella-museum.gr/informations ... iko/heroon
Hope you find it interesting.