Special Relativity

Galileo stated the Principle of Relativity using a series of thought experiments to be performed inside a ship. This was revolutionary in a time dominated by Aristotelian misconceptions, when the common wisdom was that there is an absolute rest system and a force is needed to keep objects moving. (However, the times were ripe and some of the works by Giordano Bruno (1548–1600) imply correct ideas about the relativity of motion.) The worst difficulty was that the 2000-years-old teaching of Aristotle  was upheld by the Church.