Flavius Anastasius (Φλάβιος Ἀναστάσιος) or Anastasius I (Ἀναστάσιος Β΄) (c. 430–July 9, 518) was Byzantine Emperor from 11 April 491 until his death. He was born at Dyrrhachium not later than 430. Anastasius had one eye black and one eye blue (heterochromia) , from which he was nicknamed Dicorus (Greek: Δίκορος, "two-pupiled").
The principal wars in which Anastasius was engaged were the Isaurian War and the Sassanid War. The former (492-496) was stirred up by the supporters of Longinus of Cardala, the brother of Zeno. The battle of Cotyaeum in 491 "broke the back" of the revolt, but guerrilla warfare continued in the Isaurian mountains for some years longer. In the war with Sassanid Persians (502-505), Theodosiopolis and Amida were captured by the enemy, but the Persian provinces also suffered severely and the Romans recovered Amida. Both adversaries were exhausted when peace was made (506) on the basis of status quo. Anastasius afterwards built the strong fortress of Daras to hold in check the Persians in Nisibis. The Balkan provinces were devastated by invasions of Slavs and Bulgarians; to protect Constantinople and its vicinity against them he built the Anastasian Wall, extending from the Propontis to the Euxine.
The emperor was a convinced Monophysite, but his ecclesiastical policy was moderate; he endeavoured to maintain the principle of the Henotikon of Zeno and the peace of the church. It was rebellious demonstrations of the Byzantine populace, that drove him in 512 to abandon this policy and adopt a monophysitic programme. His consequent unpopularity in the European provinces was utilized by an ambitious man, named Vitalian, to organize a dangerous rebellion, in which he was assisted by a horde of "Huns" (514-515); it was finally suppressed by a naval victory won by the general Marinus.
There is an account about his choosing of a successor: Anastasius could not decide which of his three nephews should succeed him, so he put a message under a couch and had his nephews take seats in the room, which also had two other seats; he believed that the nephew to sit on the special couch would be his proper heir. However, two of his nephews sat on the same couch (one story has it that they were incestuous lovers), and the one with the concealed message remained empty. Then, after putting the matter to God in prayer, he determined that the first person to enter his room the next morning should be the next emperor, and that person was Justin, the chief of his guards. In fact, Anastasius probably never thought of Justin as a successor, but the issue was decided for him after his death. At the end of his reign, he left the imperial treasury richer by 23,000,000 solidi or 320,000 pounds of gold.
Anastasius died childless, but had several known relatives. His brother Flavius Paulus had served as Roman consul in 496. A sister-in-law, known as Magna, was mother to Irene and mother-in-law to Olybrius. This Olybrius was son of Anicia Juliana and Areobindus. The daughter of Olybrius and Irene was named Proba. She married Probus and was mother to a younger Juliana. This younger Juliana married another Anastasius and was mother of Areobindus, Placidia, and a younger Proba. Another nephew of Anastasius was Flavius Probus, Roman consul in 502. Caesaria, sister of Anastasius, married Secundinus. They were parents to Hypatius and Pompeius. Flavius Anastasius Paulus Probus Moschianus Probus Magnus, Roman Consul in 518 also was a great-nephew of Anastasius. His daughter Juliana, later married Marcellus, a brother of Justin II. The extensive family may well have included viable candidates for the throne.
The main elements of the complex monetary system of the early Byzantine Empire, which suffered a partial collapse in the 5th century, were revived by Emperor Anastasius I (491–518) in 498. The new system involved three denominations of gold (the solidus and its half and third) and five of copper (the follis, worth 40 nummi and its fractions down to a nummus).