How did Galen contribute to he development of medicine?

Galen, a prominent Greek physician in the 2nd century AD, significantly advanced medicine through his extensive writings and dissections of animals, which laid the groundwork for anatomical knowledge. He emphasized the importance of empirical observation and experimentation, influencing medical practices for centuries. His theories on the humors and the role of the brain in controlling bodily functions shaped medieval and Renaissance medicine, making him a pivotal figure in the evolution of medical science.