The discovery of diffraction of light is often attributed to Francesco Maria Grimaldi, an Italian Jesuit priest and physicist, who conducted experiments and documented his findings in the 17th century.

However, it's important to note that:

* Earlier observations: There were observations of diffraction phenomena before Grimaldi, but they were not understood as such. For instance, Leonardo da Vinci noted the appearance of colored fringes when light passed through a narrow opening.

* Grimaldi's contributions: Grimaldi was the first to systematically study and document the phenomenon. He coined the term "diffraction" and provided accurate observations and explanations.

* Further developments: Later scientists like Robert Hooke, Isaac Newton, and Thomas Young built upon Grimaldi's work, developing a more comprehensive understanding of diffraction.

Therefore, while Grimaldi is generally credited with the discovery of diffraction, it's a complex phenomenon with a long history of observation and scientific exploration.