Three scientists are credited with the development of cell theory. Matthias Schleiden observed that all plants were made of cells; Theodor Schwann observed that all animals were also made of cells; and Rudolf Virchow observed that cells only come from other cells. The cell was first discovered and named by Robert Hooke in 1665. He remarked that it looked strangely similar to cellula or small rooms which monks inhabited, thus deriving the name.
