Thus, we found that in the historiography of Terekhtemyriv legend key role played two works – Chronicle P. Piasecki (1645) and the work of G. Grabianka (1719). The next question that should be considered – how formed the initial version of the legend by Piasecki.
A unique feature of this legend is that it was fixed immediately in four independent sources 2 quarters 17 cent.: Rutski (1626), Piasecki (1645), Sobieski (1646), Beauplan (1651). There is the idea of the common source of all records.
So we suggests in this story was reflected plan by Peter Konashevych-Sagajdachny – turn Terekhtemyriv to area free from the Polish nobility, kind of Piedmont recognized (or tolerated) by the Polish government, the basis of the national liberation struggle.
Briefly origin of Terekhtemyriv legend is under my assumption as follows: plan by Sagajdachny —> conversation with Polish officials about its elements —> folklorization in the form of oral narrative among gentry —> fixation in written sources.
This is a minimal set of assumptions, which could naturally and consistently explain all relevant facts. Fragments of noble folklore recorded by Rutski, Sobieski and Beauplan where presented Terekhtemyriv legend, but there was no a Báthory's legend.
Combining of Terekhtemyriv and Báthory's legends was carried out by Paul Piasecki. Describing the state of the Cossacks in about the form in which it was formed before the rebellion 1637 – 1638 biennium, Piasecki attributed its formation to Stefan Báthory.
It is an abstract of the chapter. For the full text see please ukrainian version.