When was the scientist that  revealed by means of microscopy the previously unknown world of microorganisms born?
Antonie van Leeuwenhoek Antonie Philips van Leeuwenhoek ( , ] ; 24 October 1632 – 26 August 1723) was a Dutch businessman, scientist, and one of the notable representatives of 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 often considered to be the first acknowledged microscopist and microbiologist. Van Leeuwenhoek is best known for his pioneering work in the field of microscopy and for his contributions toward the establishment of microbiology as a scientific discipline.
Alexander A. Maximow Alexander Alexandrowitsch Maximow (Russian: Александр Александрович Максимов ; 3 February [O.S. 22 January] 1874 - December 4, 1928), was a Russian-American scientist in the fields of Histology and Embryology whose team developed the hypothesis about the existence of "polyblasts". Maximow is renowned for his experimental work on the unitarian theory of hematopoiesis: all blood cells develop from a common precursor cell. Maximow served as a Corresponding Member of the Russian Academy of Sciences.