In 545 a truce for five years was signed, Justinian paying two thousand pounds of gold. In 549 the Romans yielded to the appeal of the Lazi and sent troops to aid them to shake off the Persian yoke. After various sieges, a new truce was concluded in 551, the Romans paying twenty-six hundred pounds of gold. Hostilities went on, none the less, with a result, as Bury[e] notes, that the Persians failed of their design to gain access to the Euxine, and “that on the waters of the sea the Romans were to remain without rivals.” The Romans had, however, to pay, as usual, the price.[a] The war had been carried on for twenty years, but during the latter period of its duration military operations had been confined to Colchis. It was terminated in 562 by a truce for fifty years, which effected little change in the frontiers of the empire. The most remarkable clause of this treaty of peace imposed on Justinian the disgraceful obligation of paying Chosroes an annual subsidy of thirty thousand pieces of gold [£18,750 or $93,750]; and he was compelled immediately to advance the sum of 210,000 pounds, for seven years. The sum, it is true, was not very great, but the condition of the Roman Empire was sadly changed, when it became necessary to purchase peace from all its neighbours with gold, and with gold to find mercenary troops to carry on its wars. The moment, therefore, a supply of gold failed in the imperial treasury, the safety of the Roman power was compromised. The weakness of the Roman Empire, and the necessity of finding allies in the East, in order to secure a share of the lucrative commerce of which Persia had long possessed a monopoly, induced Justinian to keep up friendly communications with the king of Ethiopia (Abyssinia). Elesboas, who then occupied the Ethiopian throne, was a prince of great power, and a steady ally of the Romans. The wars of this Christian monarch in Arabia are related by the historians of the empire; and Justinian endeavoured, by this means, to transfer the silk trade with India from Persia to the route by the Red Sea. The attempt failed from the great length of the sea voyage, and the difficulties of adjusting the intermediate commerce of the countries on this line of communication; but still the trade of the Red Sea was so great that the king of Ethiopia, in the reign of Justin, was able to collect a fleet of seven hundred native vessels, and six hundred Roman and Persian merchantmen, which he employed to transport his troops into Arabia.[b] THE REVOLT IN AFRICA [Sidenote: [535-545 A.D.]]