Justinian, who had always had a keen interest in theological matters and actively participated in debates on Christian doctrine, has become even more devoted to religion during the later years of his life.
When he dies, on November 14, 565, he leaves the empire exhausted by his wars and public spending, but enriched by his law code and monuments.
Justinian's body is entombed in a specially built mausoleum in the Church of the Holy Apostles (the tomb will be desecrated and robbed during the pillage of Constantinople in 1204 by the Latin States of the Fourth Crusade).
Along with Justin, the kouropalates, another of the late emperors’ nephews, Justin, son of the late Germanus, is the leading contender for the vacant throne, due to his titles and reputation as a commander, as well his army's proximity to the imperial capital.
The former, however, is already present at Constantinople, and can count on the support of the Senate, and especially of Patriarch John Scholasticus and the Count of the Excubitors Tiberius (the future Tiberius II), whom he had helped secure his post.
Callinicus, the praepositus sacri cubiculi, seems to have been the only witness to his dying moments, and later claimed that Justinian had designated "Justin, Vigilantia's son" as his heir in a deathbed decision.
Modern historians suspect Callinicus may have fabricated the last words of Justinian to secure the succession for his political ally, who is the son of Justinian’s sister Vigilantia, and married to Sophia, the niece of the late Empress Theodora.
In any case, Callinicus starts alerting those most interested in the succession, originally various members of the Byzantine Senate.
Then they jointly inform Justin and Vigilantia, offering the throne.
Justin accepts after the traditional token show of reluctance, and with his wife Sophia, he is escorted to the Great Palace of Constantinople.
The Excubitors block the palace entrances during the night, and early in the morning, John Scholasticus, Patriarch of Constantinople, crowns the new Augustus.
Only then is the death of Justinian and the succession of Justin publicly announced in the Hippodrome of Constantinople.
Both the Patriarch and Tiberius, commander of the Excubitors, had been recently appointed, with Justin having played a part in their respective appointments, in his role as Justinian's curopalates.
Their willingness to elevate their patron and ally to the throne is hardly surprising.
In the first few days of his reign Justin pays his uncle's debts, administers justice in person, and proclaims universal religious toleration.
Contrary to his uncle, Justin relies completely on the support of the aristocratic party.
Proud of character, and faced with an empty treasury, he discontinues Justinian's practice of buying off potential enemies.
Immediately after his accession, Justin halts the payment of subsidies to the Avars, ending a truce that has existed since 558.
According to the contemporary historian Evagrius Scholasticus, the two Justins had reached an agreement whereby whoever would be crowned emperor would make the other the "second man" in the empire.
When Justin II recalls his cousin to Constantinople, it seems that this is the reason.
The general is warmly received at first, but soon the new emperor begins to make accusations against him, dismisses his bodyguard and places him under house arrest, before sending him to exile in Alexandria, ostensibly as the new augustal prefect of Egypt.
