Answer:
the Bulgarian Empire.
Step-by-step explanation:
During the tenth century, the Byzantine Empire, also known as the Eastern Roman Empire, experienced a period of resurgence and expansion. One of the regions they reclaimed was the Balkans, which had been previously controlled by the Bulgarian Empire.
The Byzantine Empire, under the leadership of Emperor Basil II, launched a series of military campaigns known as the Byzantine-Bulgarian Wars. These wars spanned several decades and involved multiple conflicts between the Byzantines and the Bulgarians.
Emperor Basil II, also known as Basil the Bulgar-Slayer, sought to reestablish Byzantine control over the Balkans. Through a combination of military tactics, diplomacy, and political alliances, the Byzantines gradually gained the upper hand and were able to conquer significant portions of the Balkans.
One of the decisive battles in this conflict was the Battle of Kleidion in 1014. In this battle, the Byzantine forces, led by Basil II, achieved a resounding victory over the Bulgarian army. As a result, the Byzantines were able to secure their hold on the Balkans and extend their influence in the region.
The recovery of the Balkans by the Byzantine Empire marked a significant milestone in their territorial expansion and consolidation of power in the tenth century. It also had lasting effects on the political and cultural landscape of the region, as the Byzantine influence played a role in shaping the development of the Balkans in subsequent centuries.