In 1665 Robert Hooke documented microscopic structures, including cork, in Micrographia and used “cell” for the compartments he observed. This was not yet modern cell theory, but it was an important observational and naming milestone.
Improved microscopy later expanded the visible structures of life. Nineteenth-century cell theory organized dispersed observations into a systematic account of biological organization.
The history shows how instruments, observations, concepts and reproducible communication jointly produce scientific change.