The 15th century....I think
I heard that there are two that remained. Angola and Mozambique.
Karl Marx once said; "I am not a Marxist!". He also once called his adherents "useful idiots". Karl Marx presented a strategy in communism much of which can be found in his book, Das Kapital.
I hope I was able to help <3

the spinning wheel to produce textiles, the water wheel used to power machinery and the steam engine were invented. These inventions aided in speeding up the production of manufactured items.