Although the actual study of microbiology did not officially begin until the mid 1800's people, unofficially, recognized that some small entity caused diseases and acted accordingly.
Microbiology in Ancient Times
People living in ancient times recognized the diseases were spread through contact with other people. Examples of this can be seen in the shunning of lepers as well as during the Black Death that struck Europe resulted in many sick people being left behind. Although ancient people could see masses of microbes, such as mold that grew on food, it is doubtful that they recognized that as living organisms.
The Beginning of Microbiology
The first person to claim they saw microbes under a crude microscope was a man named Robert Hooke. Although he did see fungus on plant cells, due to the poor quality of his lens he probably couldn't actually see any bacteria. After Hooke came Anton Van Leeuwenhoek, who lived during the late 17th century and was the first person to actually see bacteria and accurately describe them. His original use was for looking at cloth but at some point he had a chance to look at something infested with microbes. His claim that what he saw was alive shocked everyone.
The Fathers of Microbiology
The two fathers of microbiology, L. Pasteur and Robert Koch, both lived during the 19th century and helped to advance the field immensely. Pasteur disproved the theory of spontaneous generation by proving that microbes grew rather than just appearing. Pasteur also invented the method pasteurization whereby only the bacteria that spoil the product are killed off. Koch however, who was a physician, became interested in anthrax. Anthrax at that time was common in both farmers and their animals. Koch also spotted a bacterium like Pasteur did, his however was found in the blood of anthrax victims and he figured that must be the cause of the disease. To prove this he isolated the bacteria and was able to introduce it into other animals and then re-isolate it. Because his experiment and techniques could be easily reproduced he quickly became famous. His way of doing experiments is still used today.
The study of microbiology has come a long way since these two men made their first discoveries. Today diseases caused by the millions of microbes that inhabit the earth can be controlled and helped through the use of antibiotics. There continue to be advances everyday in this field and much thanks should be given to those who came before and paved the way for modern scientists.