Zacharias's invention of the microscope led to the use of
this microscope by Hooke. Hooke used this microscope to observe a piece of cork, discovering cell walls.
Hooke was an english philosopher, architect, and polymath. Using the first model of the microscope, he discovered cells and the cell wall, observing a thin piece of cork. This discovery was his contribution to the cell theory in 1665.
Leeuwenhoek was a dutch scientist who took the interest in microscopes. Anton Van Leeuwenhoek was the first to see and describe bacteria in 1674. His interest led to his contribution to the cell theory, making better and more advanced microscopes.
Brown was a scottish botanist. His contributions include one of the earliest description of the cell nucleus and cytoplasmic streaming.
Schleiden was a German botanist. He stated that the different parts of the plant organism are made of cells.
Schwann was a German physiologist. found that all plants are made of cells, and he communicated this discovery to Schwann, who had found similar structures in the cells.
Virchow was a German physician, anthropologist, pathologist, prehistorian, biologist, writer, editor, and politician. Virchow suggested that all cells come from pre-existing cells. This was a major contribution to the cell theory.