Cosmas the Priest

[8] It is also an important source on life and society in 10th-century Bulgaria,[2] which is described as suffering a major crisis, the glorious days of Peter's father Simeon the Great (r. 893–927) long over.

The first section of the treatise is a vehement criticism of Bogomilism and its disobedient followers,[2][3] whom Cosmas accuses of contributing to the degradation of Bulgarian society.

[11] As Cosmas purposefully employed around 70 quotations from Apostle Paul to debunk the beliefs of Bogomils, he was very likely aware of the sect's ancestral ties to Paulicianism.

[3] The second part of the treatise contains Cosmas' criticism on contemporary Bulgarian society, with particular attention to the religious and social issues of the time.

While Cosmas was a staunch supporter of the Bulgarian Orthodox Church's policies against Bogomilism, in the second section he spares no criticism to that religious body's other practices.

[12][13] Cosmas hints that the emergence of Bogomilism should be blamed at least partially on the contemporary state of the Bulgarian Orthodox Church.

[15] The northeastern Bulgarian village of Kozma Prezviter in Omurtag Municipality, Targovishte Province, bears the name of the medieval writer.