The magnifying power of segments of glass spheres was known to the Assyrians before the time of Christ; during the 2nd century CE, Claudius Ptolemy, an astronomer, mathematician, and geographer at Alexandria, wrote a treatise on optics in which he discussed the phenomena of magnification and refraction as related to such lenses and to glass spheres filled with water. Despite that knowledge, however, glass lenses were not used extensively until around 1300 (an anonymous person invented spectacles for the improvement of vision probably in the late 1200s). That invention aroused curiosity concerning the property of lenses to magnify, and in the 16th century several papers were written about such devices.

Then, in the late 16th century, the Dutch optician Hans Jansen and his son Zacharias invented the compound microscope. The utility of that instrument in the biological sciences, however, was not realized until the following century. Following subsequent technological improvements in the instrument and the development of a more-liberal attitude toward scientific research, one microscopist emerged who had a profound effect on biology: Jan Swammerdam's Bybel der Natuure was published posthumously in 1737 by the Leiden University professor Herman Boerhaave. Convinced that all insects were worth studying, Swammerdam had compiled an epic treatise on as many insects as he could, using the microscope and dissection.