I need to know the approximate time учёный was substantivised.
Dahl has no separate entry for the word as either noun or adjective, but he does use it as a noun when defining other terms (e.g. «учоный, этимъ предметомъ занимающійся»).
The Russian corpus gave me identical-looking timelines for all instances and adjectival instances of ученый, and only a slightly different one for substantival instances. I have no idea how reliable these are.
Trying to find a direct answer doesn't lead anywhere. I'd be grateful for any pointers.