reflection either of Hobbes's thoughts about the engagement controversy or of his reaction to treatises published by Patriarchalists, such as Sir Robert Filmer, between 1640 and 1651. When in November 1640 the Long Parliament succeeded the Short, Hobbes felt that he was in disfavour due to the circulation of his treatise and fled to Paris. He did not return for 11 years. In Paris, he rejoined the coterie around Mersenne and wrote a critique of the Meditations on First Philosophy of Descartes, which was printed as third among the sets of "Objections" appended, with "Replies" from Descartes, in 1641. A different set of remarks on other works by Descartes succeeded only in ending all correspondence between the two. Hobbes also extended his own works in a way, working on the third section, De Cive, which was finished in November 1641. Although it was initially only circulated privately, it was well received, and included lines of argumentation that were repeated a decade later in Leviathan. He then returned to hard work on the first two sections of his work and published little except a short treatise on optics (Tractatus opticus), included in the collection of scientific tracts published by Mersenne as Cogitata physico-mathematica in 1644. He built a good reputation in philosophic circles and in 1645 was chosen with Descartes, Gilles de Roberval and others to referee the controversy between John Pell and Longomontanus over the problem of squaring the circle. Civil War Period (1642–1651) The English Civil War began in 1642, and when the royalist cause began to decline in mid-1644, many royalists came to Paris and were known to Hobbes. This revitalised Hobbes's political interests, and the De Cive was republished and more widely distributed. The printing began in 1646 by Samuel de Sorbiere through the Elsevier press in Amsterdam with a new preface and some new notes in reply to objections. In 1647, Hobbes took up a position as mathematical instructor to the young Charles, Prince of Wales, who had come to Paris from Jersey around July. This engagement lasted until 1648 when Charles went to Holland. The company of the exiled royalists led Hobbes to produce Leviathan, which set forth his theory of civil government in relation to the political crisis resulting from the war. Hobbes compared the State to a monster (leviathan) composed of men, created under pressure of human needs and dissolved by civil strife