Why were the ideas of Hippocrates and galen important for hundreds of years?

Galen was loved by his people mainly because he agreed with the idea of 'the one creator', this made people listen to what he says even if the idea was incorrect. this also links to the idea of Hippocrates and the 4 humors. Galen also believed in the idea of opposites, for example if you had a cold , you would need to eat or drink something hot. this shows us that he used his common sense and logic, and stayed away from supernatural ideas, like Hippocrates.

even though he couldn't dissect people, he used skeletons and bones from the grave yard. but he also used pigs and apes for his knowledge. this shows us that he was brought up in an environment were healing and medicine was well developed. even though , some of the ideas were wrong like to 2 jaw bones. people still agreed with him, because he had the same idea as the roman catholic churches, which gave him power amongst the people.