 Belisarius arrived in the East in 541 , but , after some success , was again recalled to Constantinople in 542 . The reasons for his withdrawal are not known , but it may have been instigated by rumours of disloyalty on behalf of the general reaching the court . The outbreak of the plague caused a lull in the fighting during the year 543 . The following year Khosrau defeated a Byzantine army of 30 @,@ 000 men , but unsuccessfully besieged the major city of Edessa . Both parties made little headway , and in 545 a truce was agreed upon for the southern part of the Roman @-@ Persian frontier . After that the Lazic War in the North continued for several years , until a second truce in 557 , followed by a Fifty Years ' Peace in 562 . Under its terms , the Persians agreed to abandon Lazica in exchange for an annual tribute of 400 or 500 pounds of gold ( 30 @,@ 000 solidi ) to be paid by the Romans . 
