[1][2][3] As the Byzantine-Bulgarian relations deteriorated by the end of the 960s, the Eastern Roman Empire paid the Kievan prince Sviatoslav to attack Bulgaria.

Emperor Boris II was captured and taken to Constantinople where he abdicated and the Byzantine Emperor John I Tzimiskes announced the annexation of Bulgaria, even though the Eastern Roman Empire only controlled Eastern Bulgaria at the time, and the lands to the west remained under Bulgarian control.

The four brothers David, Moses, Aron, and Samuel of the Cometopuli dynasty ruled in the free territories and in 976, launched a major offensive against the Byzantines to regain the lost lands.

Samuel proved to be a successful general inflicting a major defeat on the Byzantine army, commanded by Basil II at the Gates of Trajan and retaking north-eastern Bulgaria.

The Byzantines under Basil II, a successful general and experienced soldier, slowly gained the upper hand and from 1001, started to seize a number of important areas and towns.

[9] Roman emperor Nikephoros II Phokas (963–969), who had achieved decisive victories over the Arabs to the east[10] insulted the Bulgarian ambassadors and launched a campaign.

"[9] Soon after that military demonstration Phokas tried to restore the peace on condition that the Bulgarians would cancel their agreement with the Magyars which was refused by Peter I who reminded the Byzantine emperor that when Bulgaria needed help against the Magyars the Byzantines did not react and now that it had been forced to make peace with them it would be folly to break the treaty.

[9] In that situation Nikephoros II Phokas turned to the usual means of Byzantine diplomacy and decided to pay the Kievan prince Sviatoslav to attack Bulgaria.

[11] He was succeeded by his eldest son Boris II who had little choice but to cooperate with Sviatoslav, whose attention had by that time been diverted by Kalokyros to Constantinople.

He had to surrender the imperial insignia – the golden crown and the red boots – which were placed in the cathedral Hagia Sophia.

The three-century old Byzantine dream to eliminate the Bulgarian state and restore the imperial borders along the Danube seemed to have come true.

While the eastern parts of the empire were conquered and turned into a Byzantine province[15] the lands to the west of Iskar river remained under Bulgarian control and included most of Macedonia, Albania and the lands to the south of the Danube between the Kolubara river (including Srem) to the west and the mountains around Etropole and Ihtiman to the east.

[16] These territories were ruled by the four brothers David, Moses, Aron and Samuel, sons of the governor (komita/comes) of Serdica (Sofia) Nikola.

[22] In 995, the Fatimids attacked the eastern Byzantine cities of Antioch and Aleppo, and Basil moved east to deal with the matter.

Samuel's ability to launch attacks into the western Byzantine Empire became limited, and he lost control of the city of Dyrrachion (modern Durrës).

He wisely accepted Bulgarian taxes in kind rather than in coinage, as a full monetary economy was not established in Bulgaria.