Blackened red bricks weathered by time, partially covered by a layer of white plaster that has endured for over eleven centuries. This is the first impression of Preah Ko, the oldest standing temple of the Khmer Empire, built in 879 AD by King Indravarman I as a funerary monument dedicated to his royal ancestors and the predecessors of the founder of the empire, Jayavarman II. We are not at Angkor Wat, crowded with buses and street vendors, but about twenty kilometers east of Siem Reap, in the Roluos group, an area that mass tourist circuits often skip.
The name Preah Ko literally means Sacred Bull, a reference to the three statues of Nandi — the sacred bull of Shiva — that stand in front of the main towers. This Hindu temple dedicated to Shiva was the first major architectural project of the capital Hariharalaya, a precursor to everything that would come later in the history of Khmer architecture. Visiting it means reading a foundational chapter, not a celebratory chapter.
The architecture: six towers and the original plaster
The complex consists of six brick towers arranged in two rows, three in the front row and three in the back row, on a low platform. The front towers, taller, were dedicated to the deified kings; the back towers, slightly smaller, to their royal consorts. Unlike the large temples of Angkor, built of sandstone, Preah Ko is entirely made of brick, a construction technique typical of the pre-Angkorian period.
What makes this site visually extraordinary is the presence of traces of original white plaster still visible on the surfaces of the bricks. In some places, the decorations carved in sandstone — figures of devata, female deities, and kala, demonic masks — emerge with surprising clarity precisely because they have been protected for centuries by this layer. Observing closely the door pillars, one can still read long inscriptions in Sanskrit and in ancient Khmer carved into the stone.
The historical context: Hariharalaya and the origins of the Khmer Empire
Preah Ko was completed in 879 AD, three years after Indravarman I began his reign. It was part of a larger urban planning project that included the mountain temple of Bakong — the first stone mountain temple of the Khmer Empire — and Lolei, built shortly after by his son Yasovarman I. Together, these three temples form the Roluos Group, an ensemble that documents the transition from brick architecture to stone architecture and the evolution of the mountain temple concept as a representation of the cosmic Mount Meru.
The choice to dedicate the towers to royal ancestors was not only religious: it was a political statement. Indravarman I was legitimizing his dynasty by directly linking it to Jayavarman II, the king who in 802 AD proclaimed Khmer independence from the Javanese and unified the territory. Preah Ko was, in this sense, a manifesto carved in terracotta.
How to visit Preah Ko: practical tips
The Roluos Group is included in the Angkor Archaeological Park pass, which starts at 37 dollars for one day and covers all the temples in the area, including those of Roluos. There is no separate ticket. To reach Preah Ko from Siem Reap, the most common way is to hire a tuk-tuk for half a day: the journey takes about 25-30 minutes and many drivers know the route well. Alternatively, it is possible to rent a bicycle, but the distance and heat make this option challenging in the hottest months.
The best time to visit is early morning, between 7:00 and 9:00, when the slanting light illuminates the brick surfaces and sandstone reliefs with a quality that midday does not offer. The site is almost always quiet — a complete visit takes about 45-60 minutes — and allows you to observe the details without the pressure of crowds. Bring enough water: in the Roluos area, the stalls are few compared to Angkor.
What to Observe Up Close
Once on site, do not stop at just the main towers. Walk along the inner perimeter of the enclosure and look for the false brick portals on the sides of the towers: they are decorative, not functional, but they already showcase Khmer craftsmanship in managing brick arches. Pay attention to the figures of sandstone guardians at the sides of the entrances, some still almost intact, with details in the headdresses and jewelry that reveal influences from Indian art of the period.
Finally, the three statues of Nandi in front of the front towers deserve a moment of attention: they are modern replicas, but their position reflects the original design from 879. The sacred bull looks towards the tower, towards Shiva, as it has for more than eleven centuries. It is a small detail, but it tells the whole essence of this place.