The first compound microscope, using two or more lenses to create a magnification of 9X, was developed by the Dutch eyeglass maker Zaccharias Janssen and his father Hans around 1590. Prior to this, only single-lens magnifying glasses, commonly known as flea glasses, were available.
Janssen was also a debated inventor of the telescope, along with Dutch eyeglass-maker Hans Lippershey. The 18th century Dutch scientist Anton van Leeuwenhoek took Janssen's design, added a number of lenses to it and produced a microscope capable of 270X magnification. Van Leeuwenhoek became the first person to see objects too small to see with the naked eye, such as bacteria, yeast cells and blood corpuscles.