You’d also need to make magnets, know their polarisation, create bearings, and have the skill to assemble all of that as well.

None of that is necessary. I built a working electric motor in cub scouts using several feet of wire, tape, some iron nails, some sheet metal cut from tin cans, a wood board to mount it on, and a battery.

Tools required: tin snips and a hammer.

A battery can be made from a jar, lemon juice, and two electrodes.

Believe me, as an 8 year old, my skills were limited to using a hammer to mash my thumb with. :-)

Electromagnets substituted for magnets, and bearings were a dent in the sheet metal that the point of a nail sat in and turned. Simple and effective.

Once you showed this to a medieval craftsman, they could reproduce it and start improving it.

I’m both impressed and have learned something new. Thank you :)

I found a variant that uses magnets:

https://www.bu.edu/gk12/tommy/Electric_motors.pdf

The version I built was far simpler, and used electromagnets instead of the magnets, but you can see the general idea.

I didn't design it, I don't know where the Den Mothers got the design from. But I found it fascinating, as you could see and feel how it worked.

I built several of them. One day, I got a little bolder and replaced the battery with an A/C cord. The motor buzzed loudly and burst into flames. I learned about alternating current that day :-)

I looked it up, people knew how to make wire then. From that you could build a working telegraph system, even a telephone system, with what was available at the time.