This work reexamines the governing protocols of the priestly course rotation and its bearing upon the dates of service for the course of Abijah (Luke 1:5-9)-a datum frequently utilized in various Nativity hypotheses, yet lacking any stable consensus. Presently, there is no determinable agreement in the academic community on either the method or the conclusion. Endeavors to fix the timing of Zacharias' temple service rest upon a stark methodological divide: models that champion a fixed-point, annual restart, versus models seeking to extrapolate a continuous rotation (ordinis vagi) backward from the destruction of the Second Temple. Yet, even within the two schools of thought, there is a persistent lack of uniformity. No two consulted works offered identical dates. Through a comprehensive and scrupulous forensic audit of the evidence, this work presents, using a sound, evidence-based methodology and a unique, unrealized temporal locus, the course rotation mechanisms and the viable dates of service for Abijah across the entire proposed Nativity window from 12 ʙᴄᴇ to 1 ᴄᴇ, facilitating all current hypotheses on the subject, consequently providing the first conclusive mapping of dates for use in this branch of chronological studies.