Some of the best recent work on Roman priesthoods under the Republic has engaged with the issue of priestly authority and its role in defining the place of priesthoods vis-à-vis other centres of power, influence and knowledge. The aim of this paper is to make a contribution to this line of enquiry by focussing on the concept of priestlyauctoritas, which has seldom received close attention. The working hypothesis is that the study of priestlyauctoritasmay contribute to a broader understanding of the (...) place of priesthood in Republican Rome, and especially in the Late Republican period, from which most of the evidence derives. The link between religious authority and religious expertise requires special attention. (shrink)