* Cells were discovered long before electron microscopes existed. The first observations of cells were made by Robert Hooke in 1665 using a simple light microscope. He observed the cell walls of cork cells.
* Electron microscopes were invented much later. The first practical electron microscope was developed in the 1930s.
* Light microscopes were sufficient for the initial discovery. Light microscopes provided enough resolution to see that living things were made of tiny compartments, which we now call cells.
So, while electron microscopes are essential for modern cell biology research, they were not involved in the initial discovery of cells.
