The say that the best investment is knowledge but in ancient times, knowledge is just disregarded since they don’t have any schools back then, during those times, a person must strive hard to increase his knowledge over something that will be worthwhile for them.

That is the time of the medieval times and gold is regarded as the best form of investment.  I believe that during those times, if you have a gold coin  then you may buy a lot of things during those era.  You could even buy yourself a good slave which will do all your bidding all the time.  Now, this is not the case since people are getting smarter and no one would want to be a slave so they are studying hard.