Gandalf’s Possible Inaccuracy in the chapter “The Shadow of the Past”

[Zigûr]

Originally Posted by Gothmog, LoB

2. Three great Númenóreans became Nazgûl. We don't know how or when exactly, nor who those guys were in life but if such a transformation did occur in Númenor then the Kings would have learned about that.

According to the Tale of Years the Nazgûl appeared in 2251, but the Shadow fell on Númenor around 1800 and they began colonising Middle-earth in that time. My suspicion would be that Sauron gave three of the Nine to Númenóreans who were in charge of, or at least Men of significance in, Númenórean dominions in Middle-earth, which would lead me to imagine that they were not in Númenor when their gradual transformation into wraiths occurred.