This article provides a systematic analysis of the genealogies prefixed to the King James Bible (1611), giving the first examination of their contemporary significance and purpose, as well as the collaboration between the Hebraist Hugh Broughton and the cartographer John Speed that produced them. By placing the diagrams within the context of Speed and Broughton's greater interests, as well as through the use of several previously unstudied drafts, it will show that the genealogies had a clear polemical function, emerged from a subsidiary of the thriving field of chronology, and can be placed within a longstanding visual tradition capable of explaining many of the peculiarities on which modern scholars have remained silent. Finally, it will argue that the genealogies were an ingenious kind of ‘reading technology’ produced through a synthesis of sacred and secular scholarship that aimed to transmit the products of learned, neo-Latin scholarship to an unlearned, English readership.