Roman–Sasanian War of 421–422 participant Byzantine Empire
The Roman–Sasanian war of 421–422 was a conflict between the Eastern Roman Empire and the Sasanians. The casus belli was the persecution of Christians by the Sassanid king Bahram V, which had come as a response to attacks by Christians against Zoroastrian temples; the Christian Eastern Roman Emperor Theodosius II declared war and obtained some victories, but in the end, the two powers agreed to sign a peace on the status quo ante.