The theorem was first conjectured by [[Legendre]] and [[Gauss]] (independently) circa 1796. In 1848 and 1850, [[Chebyshev]] made significant progress towards proving the theorem using the [[Riemann zeta function]] and other [[elementary techniques|non-elementary techniques]]. His non-elementary proof was completed in 1896 by [[Hadamard]] and Charles de la Vallee-Poussin. | The theorem was first conjectured by [[Legendre]] and [[Gauss]] (independently) circa 1796. In 1848 and 1850, [[Chebyshev]] made significant progress towards proving the theorem using the [[Riemann zeta function]] and other [[elementary techniques|non-elementary techniques]]. His non-elementary proof was completed in 1896 by [[Hadamard]] and Charles de la Vallee-Poussin. |