The events outlining the development of the cell theory in chronological order are:
- Hans and Zacharias Janssen created the first microscope.
- Anton van Leeuwenhoek observed small organisms he called “animalcules.”
- Robert Hooke was the first to use the word “cell.”
- Matthias Schleiden theorized that plants are made of cells.
- Theodor Schwann theorized that animals are made of cells.
- Rudolf Virchow theorized that cells come from other pre-existing cells.