The ‘Sidney psalter’ has attracted critical attention for the extraordinary metrical versatility displayed by Philip and (mostly) Mary Sidney in their complete set of psalm paraphrases in English. Ithas not however been discussed in the context of the neo-Latin metrical usage and experiment of the latter sixteenth century described in Chapter 2, although the Sidney psalter precisely reproduces in English the literary achievement in Latin of the major Protestant psalm paraphrases by George Buchanan and Theodore de Bèze (Beza). Of great devotional and literary importance for Protestants throughout Europe, these two collections were recognized immediately by contemporaries for their literary achievement, and Buchanan’s, in particular, was routinely cited until well into the eighteenth century. Taken together, they are crucial landmarks in the development of a Protestant Latin poetics, combining the literary achievement of humanism with a distinctively Protestant emphasis upon the literal meaning of the Hebrew Bible. This chapter describes theachievement and influence of these Latin works and sets out the evidence for their direct influence upon Mary Sidney in particular.