International congress of byzantine studies belgrade, 22 27 august 2016

Francesco Dall’Aglio 
Naples, Italy; 
[e-mail]
Strategies of Usurpation: 
Boril, Ivan Asen II and the Concept of Legitimacy in Bulgarian Royal Accession
In the history of Bulgaria, very few kings have been as much vilified as Boril, who ruled the 
country from 1207 to 1218. Following the contemporary sources (mainly Akropolites and Henry 
de Valenciennes), historians have generally accused him of being an usurper, a weak ruler who lost 
land to the Latins, to the Hungarians and to internal seceders, and a useful tool in the hands of 
the Church, oppressing his own people with councils against the Bogomils. He tried to pursue the 
same aggressive politics of his predecessors, but was defeated at Philippopolis in 1208 by the Latin 
emperor of Constantinople Henry I, and had to settle for peace. His name has become a paradigm 
of bleakness, crushed between the achievements of his predecessor, his uncle Kalojan, and of his 
successor Ivan Asen II. 
Without any doubt, the strongest accusation that had been cast against Boril is that he had 
usurped the throne. He has been suspected of plotting against Kalojan, and even of organizing his 
murder on the verge of his greatest triumph, the capture of Thessalonika. After Kalojan’s death his 
three nephews, Boril, his brother Strez and their cousin Slav, where the most viable candidates to 
the throne: Boril quickly gained the upper hand marrying Kalojan’s wife, a Cuman princess, and 
securing the assistance of the Cuman troops; Strez took refuge in Serbia while Slav retired to his 
appanage in southern Bulgaria, beginning a small-scale war against Boril who, according to Henry 
de Valenciennes, took Slav’s land ‘by treason’. According to Akropolites, however, the legitimate heir 
to the Bulgarian throne was Ivan Asen, the firstborn son of Asen, the first tsar of the dynasty. Still 
a minor, he was taken away from Tărnovo and brought first in the lands of the Cumans, then to 
Galicia, because the faction loyal to him feared for his life. 
In 1217, Ivan Asen returned “to take back his father’s inheritance”, according to Akropolites, 
and besieged Tărnovo with an army of Rus’ mercenaries. The Bulgarian aristocracy abandoned 
Boril, and Ivan Asen II ruled Bulgaria until his death in 1241.
Interestingly enough, Ivan Asen’s violent actions are not considered an usurpation, neither by 
Akropolites nor by modern historians; on the contrary, his invasion has always been considered a 
necessary act to restore the legitimacy of the Asenid dynasty. But it is necessary to remember that, 
in that period, there was no established procedure for the royal succession. Since the beginning of 
the kingdom, power passed from brother to brother, that is, from the deceased ruler to the oldest 
male relative. It is unknown who was the oldest between Boril, Slav and Strez, but we cannot say that 
Boril usurped the throne because he ousted from power the child of Asen who, should we apply the 
same logic, should have been chosen as king in the moment of his father’s death, already in 1196.
The aim of the paper is to analyse the concept of ‘legitimate’ succession in the first decades of 
the Second Bulgarian Kingdom, looking for the patterns of accession to the throne. The Bulgarian 
situation will be compared to that of the neighbouring nations, especially Serbia.

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