Antony van Leeuwenhoek is often referred to as the "Father of Microbiology" due to his pioneering work with microscopes in the 17th century. While he initially built microscopes to examine cloth, he made significant discoveries when he began to investigate various samples, including water and dental plaque.
One of his major discoveries was the observation of "animalcules," which were single-celled microorganisms that he described in detail. He was the first to observe and document bacteria, protozoa, and spermatozoa, providing a new understanding of microscopic life. His work laid the foundational groundwork for the field of microbiology and significantly advanced the scientific knowledge of the microbial world.