The historical figure of Kostandin Kastrioti Mazreku is attested in Giovanni Andrea Angelo Flavio Comneno's Genealogia diversarum principum familiarum .

The mythological ancient lineages produced by Angelo in his writings are fictional constructions, which he wrote in the context of the Sacred Military Constantinian Order of Saint George, but medieval biographies are considered reliable as they are corroborated and reproduced in others sources and have been compared with archival material in contemporary research.

Angelo used the cognomen Meserechus in reference to Skanderbeg and this link to the same name is produced in other sources and reproduced in later ones like Du Cange's Historia Byzantina (1680).

[5] The various geographical links of the Kastrioti to one particular Mazrek settlement are difficult to establish with certainty as the toponym appears in widespread diffusion across many subregions historically related to the family.

Historian Paolo Petta has noted that the links to the historical Kastrioti family are preserved in the oral traditions of the Mazreku tribe in northern Albania.