c. 700 BC: The "Nimrud lens" of Assyrians manufacture, a rock crystal disk with a convex shape believed to be a burning or magnifying lens.[1]
13th century: The increase in use of lenses in eyeglasses probably led to the wide spread use of simple microscopes (single lens magnifying glasses) with limited magnification.[2]
After 1609: Galileo Galilei is described as being able to close focus his telescope to view small objects close up[5] and/or looking through the wrong end in reverse to magnify small objects.[6] A telescope used in this fashion is the same as a compound microscope but historians debate whether Galileo was magnifying small objects or viewing near by objects with his terrestrial telescope (convex objective/concave eyepiece) reversed.[7]
1619: Earliest recorded description of a compound microscope, Dutch Ambassador Willem Boreel sees one in London in the possession of Dutch inventor Cornelis Drebbel, an instrument about eighteen inches long, two inches in diameter, and supported on three brass dolphins.[8][9][10]
1621: Cornelis Drebbel presents, in London, a compound microscope with a convex objective and a convex eyepiece (a "Keplerian" microscope).
1624: Galileo improves on a compound microscope he sees in Rome and presents his occhiolino to Prince Federico Cesi, founder of the Accademia dei Lincei (in English, The Linceans).
1625: Giovanni Faber of Bamberg (1574–1629) of the Linceans, after seeing Galileo's occhiolino, coins the word microscope by analogy with telescope.
1655: In an investigation by Willem Boreel, Dutch spectacle-maker Johannes Zachariassen claims his father, Zacharias Janssen, invented the compound microscope in 1590. Zachariassen's claimed dates are so early it is sometimes assumed, for the claim to be true, that his grandfather, Hans Martens, must have invented it.[9][11] Findings are published by writer Pierre Borel. Discrepancies in Boreel's investigation and Zachariassen's testimony (including misrepresenting his date of birth and role in the invention) has led some historians to consider this claim dubious.[12][3]
1661: Marcello Malpighi observed capillary structures in frog lungs.
1665: Robert Hooke publishes Micrographia, a collection of biological drawings. He coins the word cell for the structures he discovers in cork bark.
1863: Henry Clifton Sorby develops a metallurgical microscope to observe structure of meteorites.
1860s: Ernst Abbe, a colleague of Carl Zeiss, discovers the Abbe sine condition, a breakthrough in microscope design, which until then was largely based on trial and error. The company of Carl Zeiss exploited this discovery and becomes the dominant microscope manufacturer of its era.
1957: Marvin Minsky, a professor at MIT, invents the confocal microscope, an optical imaging technique for increasing optical resolution and contrast of a micrograph by means of using a spatial pinhole to block out-of-focus light in image formation. This technology is a predecessor to today's widely used confocal laser scanning microscope.
^Robert D. Huerta, Giants of Delft: Johannes Vermeer and the Natural Philosophers: The Parallel Search for Knowledge During the Age of Discovery, Bucknell University Press, 2003, p. 126
^A. Mark Smith, From Sight to Light: The Passage from Ancient to Modern Optics, University of Chicago Press, 2014, p. 387
^William Rosenthal, Spectacles and Other Vision Aids: A History and Guide to Collecting, Norman Publishing, 1996, pp. 391–392
^Jerome Ch'en, Nicholas Tarling, Studies in the Social History of China and South-East Asia: Essays in Memory of Victor Purcell, Cambridge University Press, Jun 10, 2010, p. 215
