Final answer:
Antonie van Leeuwenhoek, a Dutch cloth merchant, developed a large collection of single-lens microscopes that he used to view microbes. His observations of single-celled organisms, which he called "animalcules", made him a significant figure in the development of microbiology.
Step-by-step explanation:
Antonie van Leeuwenhoek, a Dutch cloth merchant, developed a large collection of single-lens microscopes that he used to view microbes. In 1674, van Leeuwenhoek began describing his observations of single-celled organisms, which he called "animalcules", in letters to the Royal Society of London. His innovative microscopes allowed him to observe microorganisms in detail, and his discoveries made him a significant figure in the development of microbiology.