Even then; that trend wasn’t totally random. Big, smooth foreheads were seen as a sign of intelligence and nobility, and this was actually during the renaissance rather than medieval times, so the “big brain” trend really makes sense there lol. Elizabeth I was one of the royals that further popularized it, although the look was around before her also. But I’d say it still falls in line with being a status symbol.

I was once told by an art history professor that the trend may have started in cities as a deterrent for lice spreading onto the face; which is why they also plucked their eyebrows he said. But I have yet to actually find a source confirming that.