[Jewbacca]

Other medieval (or earlier) ideas are:

wheels
fire
monotheistic theism
democracy and the republican form of government
mechanical clocks
gun powder/modern chemistry
water mills and wind mills
eye glasses
flying buttress architecture

Etc.

Just because it’s old, doesn’t mean it’s outdated.

[headsonpikes]

Speaking of Medieval(or earlier) ideas, let me mention:

HEADS ON PIKES!