The "New Testament"
Matrix mechanics in Göttingen and Erwin Schrödinger's wave mechanics were developed in 1925 and 1926. The two theories stood in a certain competition to each other, but after many discussions they turned out to be mathematically equivalent. At that time Pauli was in close contact with Werner Heisenberg but also corresponded with Schrödinger.
This was the period in which that understanding of the (new) quantum theory crystallised and went into the literature as the "Copenhagen interpretation". In 1933 Wolfgang Pauli's review article "Die allgemeinen Prinzipien der Wellenmechanik" appeared in the "Handbuch der Physik". This work – the "New Testament" – has proved just as famous and durable as his 1921 article on relativity.