sentences:  To make matters worse, in 572 the Byzantine emperor Justin II (r. 565-578) had ordered the assassination of the Ghassanid king al-Mundhir III; as a result of the unsuccessful attempt on his life, al-Mundhir severed his alliance with the Byzantines, leaving their desert frontier exposed.The fall of Dara, the main Byzantine stronghold in Mesopotamia, reportedly drove Justin II to insanity, and control of the Byzantine Empire passed to his wife Sophia and Tiberius Constantine.The new regents agreed to pay 45,000 "nomismata" for a one-year truce, and later in the year extended this to five years, secured by an annual payment of 30,000 "nomismata".