Who Invented the Microscope?

Every schoolkid has peered into a microscope and been awed by the hidden world of skin cells and squiggly bacteria. But microscopes are also critical tools for investigating the causes of disease and taking a close-up look at the building blocks of life.

It took centuries to grasp the physics of curved lenses for magnification, and centuries more to develop the materials and technology needed to create the first functional microscopes. Over the last 100 years, physicists have pushed the limits of magnification and resolution to unimaginable levels so that today’s best microscopes can zoom down to individual atoms.

Here’s a timeline of the major milestones in making small things look bigger.

c. 710 B.C.:  When 19th-century archaeologists first excavated the ancient Mesopotamian cities of Nineveh and Nimrud, they discovered a translucent piece of polished rock crystal that some experts believe is the earliest magnifying lens.

The so-called “Nimrud lens” dates to roughly 710 B.C. and may have functioned as a crude lens or a fire-starting device, but opticians disagree on whether it was intentionally made for either of those purposes. It’s just as likely that the rock-crystal was ground and polished to make jewelry, and its optical properties were purely coincidental.  

c. 60: According to the Roman author and naturalist Pliny the Elder, when Emperor Nero attended gladiatorial events, he watched them through a “smaragdus,” the Ancient Greek word for any semitransparent green stone. While Nero’s emerald-colored "monocle” is often cited as an early magnifying device, it’s more likely that it served another purpose—as a sunshade to protect his eyes from glare.  

1021: The Arab mathematician Ibn al-Haytham, known as Alhazen, wrote the first scientific treatise on optics that led to the first “reading stones”—semiprecious stones ground into convex lenses that magnified written text. The polished lenses, often made from translucent beryl, were placed directly on the manuscript. The first reading stones arrived in Europe in the 13th century.  

c. 1280: The first eyeglasses were made in Italy with magnifying lenses made of polished beryl. They were first used by monks who strained their eyes reading and copying religious texts. The original inventor of eyeglasses is hotly debated—either Salvino degli Armati from Florence or Alessandro della Spina from Pisa—but the life-changing technology quickly caught on. In 1299, a man in Florence wrote to a friend: “I can neither read nor write without these glasses they call spectacles, newly invented, for the great advantage of old men when their sight goes weak.”  

c. 1590: A Dutch spectacle maker named Zacharias Janssen is widely credited with inventing the very first compound microscope in the 1590s, but that claim has its detractors. The source was Janssen’s son, who said—50 years later—that his father also invented the telescope. Janssen’s compound microscope was described as three sliding tubes roughly 18 inches long with two lenses inside. If Janssen was indeed the inventor, he would have barely been a teenager at the time. The real inventor of the compound microscope may have been Hans Lippershey, another Dutch eyeglass maker who patented the first telescope.  

1610: Galileo Galilei, the Italian astronomer, was one of the first scientists to experiment with both telescopes and microscopes. The first “Galilean” microscopes were rigid tubes with two lenses inside—one concave and one convex. In 1614, Galileo described his early scientific observations: “With this tube I have seen flies which look as big as lambs, and have learned that they are covered over with hair and have very pointy nails by means of which they keep themselves up and walk on glass.” In 1624, the microscope officially got its name (Greek for “small” and “to view”) from the Accademia dei Lincei, a scientific academy in Rome of which Galileo was a member.

1665: Robert Hooke, curator of experiments at the Royal Society of London, published the first scientific book on microscopy, called “Micrographia.” By examining razor-thin slices of cork, Hooke became the first scientist to glimpse cells—basic structural units of life—which he called “pores.” Hooke wrote: “I could exceedingly plainly perceive it to be all perforated and porous, much like a honeycomb, but that the pores of it were not regular.” In his book, Hooke also included detailed, copper-plate illustrations of seeds, plants and the compound eye of a fly.

1676: Some of the greatest early scientific discoveries with a microscope weren’t made by a scientist at all, but by a Dutch drape maker. Antonie van Leeuwenhoek started grinding his own microscope lenses to closely examine threads in cloth, but was awakened to the scientific possibilities of microscopes after reading Hooke’s “Micrographia.” Using simple, single-lens devices of his own construction, van Leeuwenhoek was the first person to observe living microorganisms—yeast and bacteria that he called “animalcules”—as well as human blood cells. Van Leeuwenhoek reported his findings to the Royal Society and effectively launched the science of bacteriology.  

1830: The basic design of the compound microscope didn’t change for centuries—an eyepiece, a light source, multiple lenses, mirrors and an adjustable “draw tube” to focus the specimen—but the quality of the image improved dramatically in 1830 thanks to the British optician Joseph Jackson Lister. Until the 19th century, many scientists didn’t use microscopes because the images were so blurry. The problem was impurities in the glass that caused color separation and a type of distortion called “spherical aberration.” It was Lister (father of Joseph Lister, a pioneer of antisepsis) who designed the first microscope to correct those distortions and produce truly clear images.  

1931: All early microscopes were optical microscopes, meaning light was shined on or through a specimen, which was then viewed at various levels of magnification. But even the most powerful optical microscopes were limited by the wavelength of natural light (about 400 nanometers), making it impossible to zoom in to the molecular or atomic level. The German scientists Ernst Ruska and Max Knoll created the first electron microscope, which used a beam of electrons instead of natural light. Their transmission electron microscope (TEM) analyzed the deflection of electrons as they passed through a sample, providing resolutions that were millions of times greater than those of optical microscopes.  

1942: The scanning electron microscope (SEM), also invented by Ruska, was another major scientific breakthrough. Instead of passing a beam of electrons through a sample (using TEM), a scanning electron microscope bounces a stream of electrons off the surface of the object, creating sharp, three-dimensional images of impossibly small things. In biology, SEMs are used to analyze cells, microorganisms and chemical compound structures.  

1981: How small can microscopes go? The scanning tunneling microscope (STM), invented by Gerd Binnig and Heinrich Rohrer, can observe objects as small as a single atom. The STM doesn’t use light or electrons. Instead, it points the tip of an incredibly sharp wire very close to the surface of an object and applies a voltage to measure the interactions between individual atoms. STMs revolutionized the semiconductor industry and opened the field of nanotechnology, including the manipulation of individual atoms. Ruska, Binnig and Rohrer shared the Nobel Prize in physics in 1986 for their groundbreaking work on microscopes.

1993: Even the best electron microscopes can’t observe living cells or tissues because the sample would be bombarded with damaging high-energy particles. In the 1990s, a team of researchers including Eric Betzig, Stefan W. Hell and William E. Moerner developed an ingenious way to view living tissue at the molecular level using optical microscopes. Called super-resolution microscopy, the technology uses lasers to stimulate individual molecules to glow. Super-resolution microscopes can visualize the interactions of synapses within the brain or follow individual proteins within cells. Betzig, Hell and Moerner shared the Nobel Prize for chemistry in 2014.