Seventy years ago, Linus Pauling and Robert Corey published two papers on two hydrogen-bonded configurations of the polypeptide chain. The initial note in the J. Am. Chem. Soc. was followed four months later by a more detailed report (written with Herman Branson) in the Proc. Natl Acad. Sci. USA (PNAS). Remarkably, the protein structure models were referred to as ‘spiral’ configurations in the first paper, but as ‘helical’ configurations in the second paper. What prompted this name change and why does it matter?