In this talk, I trace the development of refereeing from its origins in the early nineteenth century through the late twentieth century, and show that it was only during the 1960s and 1970s that peer review (a term that itself arose in the 1960s) came to be seen as a process central to scientific practice. Throughout the nineteenth century and into much of the twentieth, external referee reports were considered an optional part of journal editing or grant making. But in the US in the 1970s, American scientists wanted to ensure their continuing influence over funding decisions in the wake of attacks on the expert advice funding agencies like the National Science Foundation and the National Institutes of Health. To protect their role in federal grantmaking, scientists and their supporters cast peer review as the crucial process that ensured the credibility of science as a whole.