The first mention and discovery of the principles behind the pinhole camera, a precursor to the camera obscura, belong to Mozi (470 BC to 390 BC), a Chinese philosopher and founder of Mohism. Later, Aristotle (384 to 322 BC) understood the optical principle of the pinhole camera. He viewed the crescent shape of a partially eclipsed sun projected on the ground through the holes in a sieve, and the gaps between leaves of a plane tree.