Matthias Schleiden was a German botanist who, along with Theodor Schwann, is best known for founding the cell theory. He initially practiced law in Hamburg before fully focusing his attention on his hobby, botany.
Schleiden didn't care for the emphasis other botanists placed upon plant classification and preferred to study plant structure instead. While teaching at the University of Jena in 1838, he wrote ?Contributions to Phytogenesis,? where he claimed that different parts of plants are composed of cells. He also discovered and documented the importance of the cell nucleus in the cell division process.
He was born on April 5, 1804, and died on June 23, 1881.