Analysis of information sources in references of the Wikipedia article "Religion en Ukraine" in French language version.
.« When Constantinople [...] became the Christian capital of the [Roman] Empire - the New Rome - it was natural that the traditions of its see should be re-examined, especially when the pretensions of Old Rome to absolute primacy became more insistent, and its apostolic foundation also made credible. Legends about the missionary journeys of St Andrew, the brother of St Peter and in fact the first apostle to be chosen by Our Lord, were amenable to such an interpretation. [...] Moreover, Andrew's mission-field was stated to be 'Scythia', a vague geographical term in Greek usage which embraces all the northern coasts of the Black Sea from the Danube to the Don. Missionary journeys by St Andrew in the Caucasus also appear in Georgian and Armenian legends. It may be a fact that Andrew visited the Crimea (Khersonnesos), sailing (as was normal) from Sinope. On this basis Russian piety later claimed that he had then sailed up the Dnepr to Kiev and predicted its future glory as a Christian metropolis. Further elaborations of the legend go beyond the credible but this much could be believed by many in Russia. [...] The spread of the legend via its Greek sources [...] probably belongs to the second half of the eleventh century. »