The wealth of Constantinople can be seen by how Justin I used pounds/1.66 tonnes of gold just for celebrating his own consulship. By the end of his reign, Anastasius I had managed to collect for the treasury an amount of 23,000,000 "solidi" or 320,000 pounds/144 tonnes of gold. At the start of Justinian I's reign, the Emperor had inherited a surplus from Anastasius I and Justin I. Before Justinian I's reconquests the state had an annual revenue of "solidi", which further increased after his reconquests in 550. Nevertheless, Justinian I had little money left towards the end of his reign partly because of the Justinian Plague, and the Roman–Persian Wars (Justinian spent large amounts of money in annual subsidies to the Sassanian Empire), as well as his wars of reconquest in Italy and North Africa, all of which greatly strained the royal treasury. In addition to these expenses, the rebuilding of Hagia Sophia cost pounds/9 tonnes of gold. Subsidies to enemy states were also paid by Justinian's successors: Justin II was forced to pay 80,000 silver coins to the Avars for peace; his wife Sophia paid 45,000 "solidi" to Khosrau I in return for a year's truce, and then Tiberius II Constantine gave away pounds of gold each year for four years. Since Emperor Heraclius changed the empire's official language from Latin to Greek in around 620, the "solidus" (plural: "solidi") would thereafter be known by its Greek name, the "nomisma" (plural: "nomismata").