Humans have always strived to see the details of objects in magnified form through optical instruments.

As early as the 1st century B.C. Seneca, the teacher of Emperor Nero of ancient Rome, recorded that "letters, no matter how small, become large and are clearly seen through a glass bulb bottle filled with water".

At the end of the 13th century, the Italians ground glass lenses to correct and improve their eyesight.

In 1609 Italy Galileo (1564-1642) invented the first astronomical telescope, he invented his own telescope modified to see near objects, found that "flies look as big as hens", accidentally improved the microscope, his colleague Giovanni Faber The first use of the word "microscope, microscope" comes from the Greek word meaning "small" and "to look or see".

In 1663 Robert Hooke (1635-1703) improved the microscope and discovered the plant cell wall "cell".

In 1674, Antoni van Leeuwenhoek (1632-1723) made a handheld single-lens microscope with a diameter of 2-4 mm and a magnification of 100-300 times to observe protozoa, bacteria and blood cells.

In the 1830s, Chester More Hall combined concave and convex lenses to resolve chromatic aberration; in 1759, John Dolland (1706-1761) made an achromatic telescope, applied for a patent, and later used it on a microscope objective.
By the end of the 19th century, Leitz, the predecessor of Leica, was selling more microscopes than Zeiss. 1923 Leitz designed the von Eicken prism magnifier, in which the visual beam was deflected through the prism to an additional lateral eyepiece, allowing two assistants to share the same surgical field of view as the primary surgeon.

Leica lenses have a 170-year history, with the first industrial microscope in 1849, the first polarizing microscope in 1872, the first fluorescence microscope in 1876, the first commercial scanning electron microscope in 1881, the first 135 camera in 1911, the first optical warp and woof in 1921
In 1996, the first stereo fluorescence combination microscope, and in 2003, NASA sent Leica's fully automatic microscope into space with a satellite to achieve ground remote control.