From 1649 until its downfall, Milton was the Commonwealth government's Secretary for Foreign Tongues. This meant he was responsible for composing Parliament's diplomatic correspondence in other languages (mainly Latin). Effectively this meant he became the revolution’s international, public face.
Milton was also one of the Parliamentarians' most vociferous and eloquent defenders. His 1649 treatise, Eikonoklastes, offered a closely-argued justification for the regicide, in defence of individual freedom. In 1651 he was commissioned by Parliament to write a pamphlet, in Latin, justifying the revolution to an international audience. The resulting Defensio pro Populo Anglicano, an explicit rebuttal to Claudius Salmasius' Defensio regia pro Carolo I, is particularly vigourous in The Republic's defence. Salmasius' reply, (posthumously) published in 1660, is what Ellwood reads to Milton in the play.
