The lands to the west of the Iskar River remained free and the Bulgarians were able to regroup headed by the four Cometopuli brothers. By 976, the youngest of them, Samuel, concentrated all power in his hands following the death of his elder siblings. When in 976 the rightful heir to the throne, BorisII's brother Roman (r.971–997), escaped from captivity in Constantinople, he was recognized as Emperor by Samuel, who remained the chief commander of the Bulgarian army. Peace was impossible; as a result of the symbolic ending of the Bulgarian Empire following BorisII's abdication, Roman, and later Samuel, were seen as rebels and the Byzantine Emperor was bound to enforce the imperial sovereignty over them. This led to more than 40 years of increasingly bitter warfare. A capable general and good politician, at first Samuel managed to turn the fortunes to the Bulgarians. The new Byzantine Emperor Basil II was decisively defeated in the Battle of the Gates of Trajan in 986 and barely escaped with his life. The Byzantine poet John Geometres wrote of the defeat: