Cell Theory By aliciaaa Jan 1, 1590 Zacharias Janssen Invented Microscope His father Hans may be partially responsible for this as well. They are somewhat credited for the invention of the first telescope, too. Period: Jan 1, 1590 to Jan 1, 1869 Scientific Developments Jan 1, 1650 Robert Hooke Developed the Watch Balance Spring Jan 1, 1673 Anton van Leeuwenhoek Discovers Bacteria and Cells Jan 1, 1837 Theodor Schwann Develops Cell Theory, cells in the peripheral nervous system, pepson, and invention of the term metabolism Jan 1, 1838 Matthias Schleiden wrote Contributions to Phytogenesis. Co Founder of Cell Theory Jan 1, 1869 Rudolph Virchow one of the founders of social medicine. Founded the society for anthropology ethnology and prehistory