Who developed the theory that all living things are made up of tiny cells?

The theory that all living things are made up of tiny cells was developed by the scientists Matthias Schleiden and Theodor Schwann in the mid-19th century. They formulated the Cell Theory, which states that all organisms are composed of one or more cells, and that the cell is the basic unit of life. This foundational concept in Biology has been crucial for understanding the structure and function of living organisms.