Title: Cell (biology)
Content: 1632–1723: Antonie van Leeuwenhoek taught himself to make lenses, constructed basic optical microscopes and drew protozoa, such as Vorticella from rain water, and bacteria from his own mouth. ; 1665: Robert Hooke discovered cells in cork, then in living plant tissue using an early compound microscope. He coined the term cell (from Latin cellula, meaning "small room" ) in his book Micrographia (1665). ; 1839: Theodor Schwann and Matthias Jakob Schleiden elucidated the principle that plants and animals are made of cells, concluding that cells are a common unit of structure and development, and thus founding the cell theory. ; 1855: Rudolf Virchow stated that new cells come from 
Title: Antonie van Leeuwenhoek
Content:  use of the huge advantage provided by his method. He studied a broad range of microscopic phenomena, and shared the resulting observations freely with groups such as the British Royal Society. Such work firmly established his place in history as one of the first and most important explorers of the microscopic world. Van Leeuwenhoek was one of the first people to observe cells, much like Robert Hooke. Van Leeuwenhoek's main discoveries are:  In 1687, van Leeuwenhoek reported his research on the coffee bean. He roasted the bean, cut it into slices and saw a spongy interior. The bean was pressed, and 
Title: Antonie van Leeuwenhoek
Content:  Antonie Philips van Leeuwenhoek (24 October 1632 – 26 August 1723) was a Dutch businessman and scientist in the Golden Age of Dutch science and technology. A largely self-taught man in science, he is commonly known as "the Father of Microbiology", and one of the first microscopists and microbiologists. Van Leeuwenhoek is best known for his pioneering work in microscopy and for his contributions toward the establishment of microbiology as a scientific discipline. Raised in Delft, Dutch Republic, van Leeuwenhoek worked as a draper in his youth and founded his own shop in 1654. He became well recognized in municipal politics and developed an interest in lensmaking. In the 1670s, he started to explore microbial life with his microscope. This was one of the notable achievements of the Golden Age of Dutch exploration and discovery (c. 
Title: Cell theory
Content:  1665, Robert Hooke used a microscope about six inches long with two convex lenses inside and examined specimens under reflected light for the observations in his book Micrographia. Hooke also used a simpler microscope with a single lens for examining specimens with directly transmitted light, because this allowed for a clearer image. An extensive microscopic study was done by Anton van Leeuwenhoek, a draper who took the interest in microscopes after seeing one while on an apprenticeship in Amsterdam in 1648. At some point in his life before 1668, he was able to learn how to grind lenses. This eventually led to Leeuwenhoek making his own unique microscope. He made one with a single lens. He was able to use a single lens that was a small glass sphere but 
Title: Cell theory
Content:  heat, was the cause. Since this was an old Aristotelian theory still accepted at the time, others did not reject it and was not disproved until Leeuwenhoek later discovered that generation was achieved otherwise. Anton van Leeuwenhoek is another scientist who saw these cells soon after Hooke did. He made use of a microscope containing improved lenses that could magnify objects almost 300-fold, or 270x. Under these microscopes, Leeuwenhoek found motile objects. In a letter to The Royal Society on October 9, 1676, he states that motility is a quality of life therefore these were living organisms. Over time, he wrote many more 
Title: Antonie van Leeuwenhoek
Content:  Using single-lensed microscopes of his own design and make, van Leeuwenhoek was the first to observe and to experiment with microbes, which he originally referred to as dierkens, diertgens or diertjes (Dutch for "small animals" [translated into English as animalcules, from Latin animalculum = "tiny animal"]). He was the first to relatively determine their size. Most of the "animalcules" are now referred to as unicellular organisms, although he observed multicellular organisms in pond water. He was also the first to document microscopic observations of muscle fibers, bacteria, spermatozoa, red blood cells, crystals in gouty tophi, and among the first to see blood flow in capillaries. Although van Leeuwenhoek did not write any books, he described his discoveries in letters to the Royal Society, which published many of his letters, and to persons in several European countries.
Title: Iatrophysics
Content:  A key component of iatrophysical anatomy was the study of particles. This was particularly influenced by 17th century developments in microbiology, the most prominent being the microscope. Antonie von Leeuwenhoeck was a Dutch scientist who is known for his use of the microscope for identifying single-celled organisms. He was also the first to observe muscle fibers, bacteria, spermatozoa and blood flow in capillaries. Another famous figure in microbiology at the time was Robert Hooke, an English scientist most famous for his use of the microscope for the discovery of cells. In his most famous work, Micrographia (1665), he attributed “occult properties” as elementary “contrivances of nature”. Like Galileo Galilei, he shared an iatrophysical viewpoint and saw living organisms as groups of small machines. The development of the microscope was largely influential in this view.
Title: Microorganism
Content:  My work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof. Antony van Leeuwenhoek remains one of the most imperfectly understood figures in the origins of experimental biology. The popular view is that Leeuwenhoek worked in a manner that was essentially crude and undisciplined, using untried methods of investigation that were lacking in refinement and objectivity. He has 
Title: Antonie van Leeuwenhoek
Content: infusoria (protists in modern zoological classification), in 1674 ; bacteria, (e.g., large Selenomonads from the human mouth), in 1683 ; the vacuole of the cell ; spermatozoa, in 1677 ; the banded pattern of muscular fibers, in 1682 Antonie van Leeuwenhoek made more than 500 optical lenses. He also created at least 25 single-lens microscopes, of differing types, of which only nine have survived. These microscopes were made of silver or copper frames, holding hand-made lenses. Those that have survived are capable of magnification up to 275 times. It is suspected that van Leeuwenhoek possessed some microscopes that could magnify up 
Title: List of Dutch inventions and innovations
Content:  Using an improved simple microscope, in 1673 Antonie van Leeuwenhoek becomes the first to discover, observe, describe, study and conduct scientific experiments with single-celled organisms, which he originally referred to as animalcules, and which now referred to as micro-organisms or microbes. For these observations he created at least 25 simple microscopes, of differing types, of which only nine survive. His simple microscopes were made of silver or copper frames, holding specially shaped single glass sphere that acted as a small lens. The smaller the sphere, the more in magnified. Those that have survived are capable of magnification up to 275 times. It is suspected that Van Leeuwenhoek possessed units that could magnify up to 500 times.

Question: what did anton van leeuwenhoek contribute to our knowledge of cells?
Answer: microscope first used by anton van leeuwenhoek.