The earliest known written record of the camera obscura is found in the Chinese text called Mozi, dated to the 4th century BCE, traditionally ascribed to and named for Mozi (circa 470 BCE-circa 391 BCE), a Han Chinese philosopher and the founder of Mohist School of Logic. These writings explain how the image in a "collecting-point" or "treasure house" is inverted by an intersecting point (pinhole) that collects the (rays of) light. Light coming from the foot of an illuminated person were partly hidden below (i.e., strike below the pinhole) and partly formed the top of the image. Rays from the head were partly hidden above (i.e., strike above the pinhole) and partly formed the lower part of the image. This is a remarkably early correct description of the camera obscura; no other known examples are dated before the 11th century.