During the last centuries, many scientists and inventors from Romania made important discoveries and inventions, making the country well known abroad. Some key Romanian discoveries were made after the second half of the 19th century and include contributions to aviation history, important findings in medicine, biology, chemistry and physics. Notable Romanian inventors and scientists include Traian Vuia who made early flights in 1906, Petrache Poenaru who invented the fountain pen in 1827, and Nicolae Paulescu who discovered insulin in 1921.