Hilbert was a well-known mathemtician during this time. When Heisenberg was first trying to solve his matrix problem, Heisenberg suggested he try and find the differential equation that would correspond to his matrix equations. If he had taken his advice, Heisenberg may very well have discovered the Schrödinger equation before Schrödinger. The connection between these different branches of mathematics was soon obvious to the mathematicians who were able to show that Heisenberg's Matrix Mechanics and Schrödinger's Wave Mechanics were absolutely equivalent. This led Hilbert to exclaim "This will not do. Physics is obviously far too difficult to be left to the physicists!" (And mathematicians still think they are God's gift to science!! :-) )