Why did no one dare criticise Galen?

No one dared criticize Galen due to his immense authority and influence in the fields of medicine and philosophy during the Roman Empire. His extensive writings, which synthesized earlier medical knowledge with his own discoveries, became foundational texts that dominated medical education for centuries. Additionally, his reputation as a skilled physician and the backing of powerful patrons made dissent risky for contemporaries, as criticism could lead to social or professional repercussions. This created an environment where his ideas went largely unchallenged for many years.