Justin was a Thracian by race, magnanimous and capable in all matters and an avid builder.
Theophanes, Chronographia, 565/66
On his deathbed Justinian named his nephew Justin as his successor. Immediately the weaknesses brought about by Justinian's conquests began to show, perhaps exacerbated by Justin's decision to reverse many of his uncle's policies. In 568 the Lombards crossed into Italy and proceeded to seize much of the country, the Byzantine provinces were reduced to coastal enclaves that could only be supplied by sea. To the north the Slavs and the Avars, to whom Justin refused to pay tribute as his uncle had done, pressed against the Danube frontier and the Berbers continued to harass the Byzantine possessions in Africa. Justin stopped paying the Persians the subsidies with which Justinian had bought peace in the East, freeing his armies up for campaigns in the West, beginning half a century of near continuous war between Byzantium and Persia. After a series of disasters in both the Balkans at the hands of the Avars, and in the East because of Persian victories, Justin was forced to resume tribute payments. In another break with the policies of Justinian, Justin chose to attempt a reconciliation with the Monophysites, a move which ultimately failed. Toward the end of his life Justin began exhibiting signs of a mental illness: he reportedly bit courtiers and displayed other erratic behavior. Contemporaries blamed the news of the loss of Dara, an important frontier fortress, to the Persians for Justin's madness.
The seals of Justin conserve his uncle’s design of a frontal imperial bust, nimbate, wearing a helmet with a diadem, pendilia, and chlamys on the obverse, and on the reverse Winged Victory flanked by crosses and holding two wreaths. The copper coins include a new type, not depicted on seals, that show Justin and his wife Sophia seated on a double throne.