In 1665 Robert Hooke discovered cells under a microscope on a cork slide
In 1670 Anton van Leeuwenhoek looked at pond water with an improved microscope, and he saw cells. He began to explore them more.
In 1830, Matthias Schleiden proposed that cells are the basic building blocks of plants.
In 1839, Theodor Schwann put together the “cell theory” which concludes that not only plants are made of cells animal tissue as well, so the cell is the basic unit of structure in all living things and all organisms have one or more cells.
In 1855, Rudolf Virchow He added a third part of the “cell theory” which was that all cells come from existing cells.