Bagan is the present-day standard Burmese pronunciation of the Burmese word Pugan derived from Old Burmese Pukam .
Arimaddana Pura (Pali: Arimaddanapura) is a classical name of the city of Bagan (Pagan). It means the “City that Tramples on Enemies.”
Its other names in Pali are in reference to its extreme dry zone climate: Tattadesa (“parched land”), and Tampadīpa ( “bronzed country”).The Burmese chronicles also report other classical names of Thiri Pyissaya (Pali: Siripaccaya) and Tampawaddy (Pali: Tampavatī).
Thiri Pyissaya also spelled Thiri Pyitsaya and Siripaccaya) is a classical name of the city of Bagan (Pagan). According to the Hmannan Yazawin chronicle, King Thinli Kyaung I (344–387 AD) moved the palace to Thiri Pyissaya, not far from the original site at Arimaddana (modern Nyaung U). It ceased being the site of the palace when King Thaik Taing (516–523 AD) moved the palace to Tampawaddy, near Thiri Pyissaya. See: Bagan Dynasty
The chronicle Zatadawbon Yazawin disagrees with Hmannan, stating that the city was founded on Thursday, 1st waxing of Pyatho 312 Saka Era (Saturday, 22 December 390 CE). However, archaeological evidence so far indicates that the earliest human settlement in the Pagan region dates only from the mid-7th century CE.Therefore the date may likely be the Burmese calendar. Indeed, 1st waxing of Pyatho 312 ME (12 December 950 CE) was a Thursday.