In 1927 Artin proved his general reciprocity law which admitted a completely new perspective on class field theory. Five years later, in 1932, Hasse succeeded to give a proof of Artin's law based on a local-global principle; this paved the way to various generalizations which are investigated today. We shall report on the development in the years between 1927 and 1932, from Artin's law to Hasse's result. Our main source are the letters which had been exchanged between Hasse and Artin in that time period, mirroring the excitement which prevailed among our protagonists. Emmy Noether and Richard Brauer too were involved in this development.