A fifty years' truce between Persia and Rome is finally negotiated, probably at the end of 561; Constantinople agrees to pay an annual tribute of thirty thousand solidi (gold coins); in return, the Persians renounce all claim to Lazica, an important bulwark against northern invaders, and undertake not to persecute their Christian subjects.

Justinian has thus maintained his eastern provinces virtually intact in spite of the vigorous offensives of the Persian king, so his policy on this front can hardly be described as a failure.

The treaty also regulates trade between Rome and Persia, since rivalry between the two great powers has always had its economic aspects, focused primarily upon the silk trade.

Raw silk reaches Constantinople through Persian intermediaries, either by a land route leading from China through Persia or by the agency of Persian merchants in the Indian Ocean.

The need to break this Persian monopoly had led Justinian to search for new routes and new peoples to serve as intermediaries: in the south, the Ethiopian merchants of the kingdom of Axum; in the north, the peoples around the Crimea and in the Caucasian kingdom of Lazica, as well as the Turks of the steppes beyond the Black Sea.

Other valuable commodities are exchanged in the Black Sea region, including textiles, jewelry, and wine from East Rome for the furs, leather, and slaves offered by the barbarians; yet, silk remains the commodity of prime interest.

It is fortunate, then, that before 561, East Roman agents had smuggled silkworms from China into Constantinople, establishing a silk industry that will liberate the empire from dependence on Persia and become one of the medieval Greek empire's most important economic operations.