Prior to the 1500’s not much was really known about the structure or function of cells. Some scientists theorized that structures like cells existed but without a way to see them their research only went so far. The earliest forms of microscopes were simple hand lenses and eventually more complex microscopes were developed allowing scientists to see the structure of cells more clearly and thus understand cells on a deeper level. The work of many, many scientists have built the body of knowledge about cells that we know today. We now know about the structures of various types of cells, cell functions, how cells make more cells and we know that all living organisms are made up of cells. Below you will see a time line of a few scientists who have contributed to the discovery of cells and who have helped us understand what we now know about cells.