We are back to our lost empires. We still have a couple Pacific Island Empires left, but we are going to switch to a new area. In this case there is a little bit better of an historical record of them because Chinese observations of them have been preserved. But as with the other Empires/Cultures/Civilizations we have noted, the extreme extent of the loss is amazing.
The Funan Empire (~100 AD to ~500 AD) is the first in a series of large organized states that existed in Cambodia.
Speaking on the Funan:The cyclical quality of ancient states is abundantly evident in mainland Southeast Asia, where multiple and overlapping histories of collapse and regeneration characterized the region from the first millennium AD onward (Miriam T. Stark, From Funan to Angkor: Collapse and Regeneration in Ancient Cambodia, p144, pdf)
(next two citations reverse order)One of the earliest and most important polities in this process emerged in the rich alluvial lowlands of the Mekong delta of southern Cambodia and Vietnam. Described in detail by visiting Chinese emissaries and linked intimately to the international maritime trade network that circulated good from China to Rome, the Mekong delta formed an economic and administrative hub in the region from the early to the mid first millennium AD. This was the time of international maritime trade, with overland and ocean routes that linked Han China with the Roman empire through South and Southeast Asia...
Chinese emissaries described multiple and competing capitals that housed elites in their wooden palaces, and libraries that were filled with documents...
Without going into too many details, the Funan were somewhat like their areas Phoenicians, but a little harder to get at, and much richer hinterland to support it, they were able to maintain their own society and culture much more readily.The indigenous documentary record for this period is thin; only three of four inscriptions, all in Sanskrit, predate the seventh century in southern Cambodia and Southern Vietnam (ibid p 149).
Much like the Phoenicians, they were highly literate, with large libraries.
Also, like the Phoenicians, we know almost nothing of their writing. If they had a Plato, Socrates, or Shakespeare, it is all lost.
No barbarians came storming over the border, so much of the agricultural-farming system remained in place, or at least recovered quickly. But after the Funan, their was very little trade with outside areas, and Cambodia started turning inward. What exactly happened is obscure enough that it is difficult for the amateur interloper (myself) to even hazard an educated guess. Some suggest Brahman forces from the south moved in, some Khmer (Chenia) from the north. That it is that much in contention further indicates how obscure this once highly literate group have become.