| Conflict: | Siege of Theodosiopolis |
| Partof: | the Anastasian War |
| Date: | August 502 |
| Place: | Theodosiopolis (modern-day Erzurum, Turkey) |
| Result: | Sasanian victory |
| Combatant1: | Sasanian Empire |
| Combatant2: | Byzantine Empire |
| Commander1: | Kavadh I |
| Commander2: | Constantine |
The siege of Theodosiopolis occurred in August 502, during the opening stages of the Anastasian War. The Sasanian ruler Kavadh I laid siege to the city of Theodosiopolis, a major Byzantine stronghold in western Armenia.
The chronicler Joshua the Stylite wrote in 507 that the general Constantine rebelled against emperor Anastasius I Dicorus, and then surrendered Theodosiopolis to the Sasanians. Joshua then writes that "Kawad (Kavadh I) consequently plundered the city, and destroyed and burned it; and he laid waste all the villages in the region of the north, and the fugitives that were left he carried off captive." Kavadh I then promoted Constantine general, before marching on.[1]
After the successful siege, Kavadh I besieged other Byzantine cities, such as Amida.