What did matthias schleiden contribute to the cell theory

He was the firs who claimed that organism is composed of cells.

Explanation:

Together with Theodor Schwann and Rudolf Virchow, a German botanist Matthias Schleiden was a cofounder of cell theory. He studied plant structure under the microscope and there he discovered that the basic units of plant organism are cells. He was also involved in the findings about the cell nucleus and the cell division process.

i'd think it's paralell