The scientific study of the world has its roots inMesopotamia. Followingthe invention of agriculture and writing, people had the time to devote to study and the means to pass the results of those studies on to the next generation. Early science was inspired by the wonder of the night sky. From the fourth millennium BCE, Sumerian priests studied the stars, recording their results on clay tablets. They did not leave records of their methods, but a tablet dating from 1800 ВСЕ shows knowledge of the properties of right-angled triangles.