Diffraction: the first recorded observation

The discovery of diffraction by Francesco Maria Grimaldi is described. He described the experiments that led to its discovery in the book De Lumine, first published in 1665, two years after Grimaldi´s death. Grimaldi´s life and his experimental observations are described. Newton´s disregard of Grimaldi´s work and substitution of the word inflexion for diffraction are discussed.<>