Analysis of information sources in references of the Wikipedia article "Pimen, Metropolitan of Kiev" in English language version.
Pimen, arriving late August or September 1379, was ordained in June 1380 after a 10-month residence in Constantinople.
[...] in the spring of 1380 Pimen, generally known in Constantinople not to be the grand prince's original candidate for the Moscow metropolitanate, was consecrated by the new patriarch, Nilus, as 'Metropolitan of Kiev and Great Russia' [...]