When European Christians came across pre-existing knowledge, they deemed it as a "discovery." Stealing knowledge from native cultures was turned into a story of how this knowledge was "discovered" by the "world."
Thus Galileo "discovered" the earth moves around the sun, though this was well known in India. Newton "discovered" calculus, though it was taken by Jesuit priests from India.
Similarly Columbus "discovered" the Americas though it was obviously known to the natives who lived there, and to others.
This theft was cast as discovery, based on the Christian "Doctrine of Discovery" which decreed that all land (and knowledge) in the world belonged to the Christian god; and non-Christians were merely squatters on it.
This allowed Christian colonizers to feel morally justified in stealing other people's wealth and knowledge, while turning theft holy, and those from which it was stolen as undeserving "barbarians."
In fact, the only undeserving barbarians were the Christian colonizers.