Nestor the Chronicler

Nestor the Chronicler (c. 1056 – c. 1114) was a monk of the Monastery of the Caves in Kiev and a prominent author in Kievan Rus'. He is firmly credited with writing two major hagiographies: the Life of the Venerable Theodosius of the Kiev Caves and the Account about the Life and Martyrdom of the Blessed Passion Bearers Boris and Gleb.

The Primary Chronicle (or Tale of Bygone Years) was traditionally attributed to Nestor, giving him the epithet "the Chronicler". However, most modern scholars doubt his authorship; as a result, some historians prefer to call him Nestor the Hagiographer.

Notable works: Primary Chronicle

Source: Wikipedia — https://en.wikipedia.org/wiki/Nestor_the_Chronicler