He invented the microscope which was the base for the cell theory.
Robert hooke discovered the cell in 1665. He said they looked like the walls a monk would live in. But he did not know how they worked.
He intensified and cleared up the lenses in the microscope to better them.
Theodor worked with matthias to formulate the informal belief as a principle of biology.
He stated the different parts of the cell and that plants are made out of individual cells
He took theador schwanns work to make it better (worked off of it). He brought the attention to the theory of cells.