Robert Hooke discovered cells in 1665 by examining a piece of cork under a microscope, coining the term "cell" from its resemblance to small rooms (cella in Latin).
Matthias Schleiden proposed in 1838 that plants are composed of cells, leading to the formulation of the cell theory.
Theodor Schwann extended the cell theory to animals in 1839, stating that all living organisms are made up of cells which are the basic units of structure and function.
