At its height Bagan held thousands of temples inside a fairly small plain, a building boom driven by a king who wanted the merit as much as the monuments.
A king builds a capital of temples
King Anawrahta, who founded the Pagan Kingdom's dominance in the eleventh century, is credited with consolidating Theravada Buddhism as the kingdom's dominant religious identity, drawing on Mon Buddhist scholarship and relics obtained partly through conquest of the Mon kingdom of Thaton. Anawrahta and his successors, along with wealthy nobles seeking religious merit, built temples across the plain at a pace that by the thirteenth century had produced several thousand structures, of which around two thousand survive today in some form.
Two temples worth naming
The Ananda Temple, completed around 1105, is considered one of Bagan's finest for its symmetry and four large standing Buddha images facing each cardinal direction. The Shwezigon Pagoda, begun under Anawrahta and completed after his death, established a gilded stupa design later widely copied across Myanmar.
What ended the boom
Bagan's dominance declined after Mongol incursions into the kingdom in the late thirteenth century destabilised central authority, and construction on the earlier scale did not resume once political power fragmented among smaller successor states.