| Prasat Ak Yom
The remains of Prasat Ak Yom are to be found on the south side of the western baray, at about one kilometre east from its south-west corner. Since the raising of the water level one can only get there by boat, on condition that the vegetation around the temple itself is cleared.(44)
While perhaps of little interest to the tourist, these ruins, though not entirely cleared, are of great archaeological importance since they are in fact the oldest in the region - older even than the first Angkor. Excavation work took some effort due to the amount of earth that needed moving - it was even necessary to blast the dike of the baray, under which the sanctuaries where buried.
Probably started in the 7th century but not taking final form until the beginning of the 9th - with alterations evident in the re-use of many of the stones - Ak Yom must have been partially buried when the axial road west from the first Angkor (the city of Bakheng) was established, to then completely disappear in the 11th century under the additional mound of the southern bank of the present baray when this was formed. Inscriptions on the jamb stones of the openings and on a "stone of the nine divinities" give respectively the dates of 609, 704 and 1001 and reveal that the temple was dedicated to the god Gambhiresvara.
Although not yet a true tiered pyramid like the "temple-mountains" dedicated to the cult of the "Devaraja" or royal linga, Ak Yom, with its terracing on three levels - the first of which is marked by a simple brick wall enclosing an earth embankment - already shows, however, clear analogies with this formula. One can assume that it must have been central to the "city of the baray" investigated by Philip Stern, the construction of which he dated between the departure of king Jayavarman II for Phnom Kulen and the accession of Indravarman in 877. Several other remains, evidently of pre-angkorian design, have been found in the surrounding area.
The monument is entirely in brick, with only the surrounds of the sanctuary openings formed in sandstone. On a base platform of a hundred metres each side, the two upper tiers were also paved in brick, with the retaining walls decorated with applied projecting motifs that recall the base elements of Cham towers. The second tier carries four corner towers and two others that are intermediate on each side, making a total of 12, while the third has a single tower raised high. Investigations have shown that this sanctuary - formerly opening to the east with three false doors and in the same style as the pyramid and the secondary sanctuaries - must originally have been covered with a timber framework - the holes for the supporting posts of which can still be seen in the walls. These were then enclosed in a thicker skin of masonry capable of carrying a corbelled brick vault and pierced with openings to the four cardinal points.
The 5m.50 square sanctuary chamber contains a large pilastered pedestal of 2m.75 that probably carried a linga. Below it, a well has at its bottom a paved underground chamber at a depth of 12m.25 that is level with the surrounding plain. This chamber formed a square of 2m.70 each side, was vaulted in brick and must have contained some sacred deposit. It was the existence of this well that subsequently led G. Trouvé to undertake similar research at the Bayon and at Angkor Wat, and so to the discovery of the foundation deposit of this latter and the Great Buddha - the guardian of the kingdom's destiny - of the former.
The ornamentation of Ak Yom provides some rare evidence of the primitive art - the lintels, often re-used, are slim in height and simplistic in composition. In some places they incorporate medallions and pendants, while in others, branches and terminal scrolls with an invasion of foliage. The colonnettes have been made cylindrical with a relatively charged ornamentation of beads and leaves on the rings. The "hipped" devatas sculpted in the brickwork are still visible on the south-east sanctuary, where there is also a remarkable false door on the east side. On the panels, small lions in circular medallions are set on a band of leaves in a crossing motif.