Guillaume de Beauplan (1640 's)
The next mention of relics belonging Guillaume de Beauplan, who was in Ukraine since the early 1630's until 1648, and repeatedly visited Kiev. On St. Michael's Cathedral he wrote:
It shows the relics of St. Barbara [Barbe], which is said to have been moved here during the wars in Nicomedia [Nicomedie] [Beauplan G. L. . – Kyiv: Naukova Dumka, 1990, p. 27]
Beauplan believed that these relics had Byzantine origin ("were moved"). Nicomedia as the city where those relics came from – in my opinion, the result of the Beauplan's encyclopedic searches (above we saw that some versions included that Barbara lives in Nicomedia). The question, how Beauplan imagined history of Byzantium and what wars he had in mind – I'll leave to the side. For us it is important, first, that the Beauplan's view remained his personal achievement and found no trace of the subsequent history of Kyivan Barbara, and secondly, that there was no generally accepted theory of the origin of these relics in Beauplan's time, because he had put forward his own hypothesis instead to paraphrase finished legend.