This collection of five temples, huddled to the north of the northern Khleang, (more or less opposite Tep Pranam), is largely ignored by most Angkor visitors.
However, if time allows, it is well worth a wander through, and you'll have the advantage of having the place pretty much to yourself. The partly forested and monkeyed location with small moats and ponds dotted around makes for a great setting for some unusual little temples — even if their origin and purpose remains a mystery.
They clearly date from different periods yet were all built close together in a relatively small area close to the centre of Angkor Thom, so were obviously of great significance to the rulers who built them. Some of the later Pithu temples are among the last stone constructions to be found at Angkor and some were added to as late as the 16th century. Many are now in a fairly ruinous state though they contain interesting carvings — lots of which are just lying around on the ground.
The earliest seems to be Temple Y — situated on a small hill — which is in the style of Angkor Wat so provisionally dated to the reign of Suryavarman II, though no inscriptions have been found at any of this group. Several interesting lintels representing scenes from Hindu mythology survive.
Temple U appears to date to the same period, with typical Angkor Wat period subjects for its carving subjects, though it is significant that the Churning of the Sea of Milk depicted there runs from East to West rather than North to South — a total Hindu faux pas which is difficult to imagine Suryavarman letting his workers get away with! The high and steep sandstone base for Temple U is also Angkor Wat style though it may well be a case of a later, unknown king copying his more glorious predecessor's work.
Temple T, also on a high sandstone base, is equally difficult to date, possessing some Bayon-style features, apsaras with some classic Hindu mythological images again carved in unorthodox ways. It also has the classic naga-lined entrance platform typical of late Bayon and Indravarman II period. As with the other temples in the group it appears that they were added to and 'upgraded' over time by different kings which emphasises their importance.
Temple V seems to be of a later date — even post-Bayon, and with its Hindu themes may possibly be one of the rare constructions from the reign of Jayavarman VIII. It is also pretty ruined and again set on a high sandstone base. (You get some good views from the tops of some of these temples.)
The most recent of the group is Temple X — a single sandstone tower built on a massive sandstone platform. Whenever the initial construction was made, the carvings are now exclusively Buddhist at this temple and of a late Thai-style period (14th - 16th century) making this a unique temple at Angkor in that it is the only one obviously belonging to the Theravada rather than Mahayana Buddhist faith. Check out the central shrine where the interior is covered in seated Buddhas!