Battle of Spercheios The Battle of Spercheios ( Bulgarian : битка при Сперхей , ) took place in 997 AD , on the shores of the river of the same name in present - day central Greece . It was fought between a Bulgarian army led by Tsar Samuil , that in the previous year had penetrated far south into Greece , and a Byzantine army under the command of Nikephoros Ouranos . The Byzantine victory virtually destroyed the Bulgarian army , and stemmed its raids in Macedonia and southern Greece , heralding a reversal of Byzantine fortunes in the prolonged conflict . The major historical source on the battle comes from Greek historian John Skylitzes whose Synopsis of Histories ( Σύνοψις Ἱστοριῶν ) contains a biography of the then reigning Eastern Roman Emperor , Basil II . Origins of the conflict . After the major success of the Bulgarians in the Battle of the Gates of Trajan in 986 , Byzantium descended into a civil war , further exacerbated by the conflict with the Fatimids in Syria . Tsar Samuil took advantage of the situation and conquered virtually the whole of the Balkan Peninsula , excluding the parts of Thrace closest to Constantinople , and southern Greece . He managed to seize many castles in the surroundings of Byzantium ' s second largest city Thessalonica . Every year he led campaigns against the Byzantines and plundered their territories . In 991 the Byzantines managed to capture the emperor Roman of Bulgaria but this did not stop Samuil who was now " de facto " the only emperor of Bulgaria . In 996 he ambushed and destroyed the forces of the " strategos " of Thessalonica and marched to the south , eventually threatening Corinth . The battle . On his way back he met a Byzantine army on the opposite side of the Spercheios river , led by the Domestic of the West , Nikephoros Ouranos . Basil II had appointed Ouranos commander of all Balkan territories of the Byzantine Empire and gave him a large army to cope with the Bulgarians . He followed the Bulgarian army and confronted it after the Bulgarians went through the Thermopylae pass on the river of Spercheios . Due to heavy rainfalls , the river had swollen and flooded a large area on both shores . The Bulgarians camped on the southern shore and the Byzantines on the northern , separated from each other by the river . The two armies remained thus encamped for several days . Samuil was confident that the Byzantines could not cross , and neglected taking measures to protect his camp . Ouranos however , sought and found a ford , leading his army across during the night , and attacking the Bulgarians at dawn . The Bulgarians were not able to put up effective resistance , and the larger part of their army was routed . Samuil himself was wounded and he and his son Gavril Radomir evaded capture by feigning death among the bodies of their slain soldiers while 12 , 000 of their men were said to be captured . After nightfall they set off to Bulgaria and in the Pindus mountains gathered the remains of their army . Due to the difficult 400 km journey to Ochrid his arm healed at an angle of 140° . According to Yahya of Antioch , Nikephoros Ouranos returned to Constantinople with one thousand heads of Bulgarian soldiers and twelve thousand captives . Aftermath . The battle was the first major defeat of the Bulgarian army . At first Samuil showed readiness for negotiations but upon the news of the death of Bulgaria ' s Emperor Roman in prison , he was proclaimed Emperor and continued the war . Although Samuil managed to recover and conquer Serbia , the Byzantines gradually took the lead in the war . In 1014 they decisively defeated the Bulgarians and four years later the Bulgarian threat to the Eastern Roman Empire had been neutralized . According to Skylitzes the victory was entirely Ouranos ' achievement and Basil II is credited with little besides appointing him to the office of Domesticos .