Eventually the crops failed and thousands perished. In 483, a severe drought affected the region and lasted for two years, during which time tensions between the Romans and Persians heightened as Arab nomads allied to the Persians raided Roman territory, causing the Romans to assemble an army on the frontier to counter such raids. The situation was defused, however, by the marzban of Nisibis and Nestorian metropolitan bishop of Nisibis, Barsauma.[13] Three years into the reign of Kavadh I, in 491, an uprising in Armenia encouraged the Qadishaye tribesmen south of Singara to revolt and besiege Nisibis.