[9] Traditional Since the time of Jayavarman VII, the Bayon has undergone numerous Buddhist additions and alterations at the hands of subsequent monarchs.

In the first part of the 20th century, the École Française d'Extrême Orient took the lead in the conservation of the temple, restoring it in accordance with the technique of anastylosis.

Because the temple sits at the exact centre of Angkor Thom, roads lead to it directly from the gates at each of the city's cardinal points.

The temple itself has no wall or moats, these being replaced by those of the city itself: the city-temple arrangement, with an area of 9 square kilometres, is much larger than that of Angkor Wat to the south (2 km²).

Though highly detailed and informative in themselves, the bas-reliefs are not accompanied by any sort of epigraphic text, and for that reason considerable uncertainty remains as to which historical events are portrayed and how, if at all, the different reliefs are related.

Its bas-reliefs, later additions of Jayavarman VIII, are in stark contrast to those of the outer: rather than set-piece battles and processions, the smaller canvases offered by the inner gallery are decorated for the most part with scenes from Hindu mythology.

Some of the figures depicted are Siva, Vishnu, and Brahma, the members of the trimurti or threefold godhead of Hinduism, Apsaras or celestial dancers, Ravana and Garuda.

One gallery just north of the eastern gopura, for example, shows two linked scenes which have been explained as the freeing of a goddess from inside a mountain, or as an act of iconoclasm by Cham invaders.

Originally, it is believed, the Bayon had been designed as a single-level structure, similar in that respect to the roughly contemporaneous foundations at Ta Prohm and Banteay Kdei.

At the time of the temple's foundation, the principal religious image was a statue of the Buddha, 3.6 m tall, located in the sanctuary at the heart of the central tower.

During the reign of Hindu restorationist monarch Jayavarman VIII(Khmer: ព្រះបាទជ័យវរ្ម័នទី ៨), the figure was removed from the sanctuary and smashed to pieces.