The optical microscope first appeared in the 1590s, but the use of microscopes for research did not gain acceptance until the 1660s. It was then that English natural philosopher Robert Hooke began an extended set of experiments with the microscope on plants, insects and combustion and respiration. The large plates in his Micrographia, created with the support of architect Christopher Wren, confirmed the value of the microscope for discovering natural worlds previously invisible to the human eye.