In the twentieth century, however, Marxist historians introduced the use of the term "English Revolution" to describe the period of the English Civil Wars and Commonwealth period (1642–1660),[2] in which Parliament challenged King Charles I's authority, engaged in civil conflict against his forces, and executed him in 1649. This was followed by a ten-year period of bourgeois republican government, the "Commonwealth", before the monarchy was restored under Charles' son, Charles II, in 1660, who was retroactively declared to have been the legal and rightful monarch ever since the execution of Charles I.[3][4] This resulted in a return to the status quo in many areas, however a number of gains made by parliamentary forces remained in law.[5][6] As far back as 1892, Friedrich Engels was recognising the event as "the Great Rebellion", and calling the Glorious Revolution of 1688 "comparatively puny", although still recognising it as part of the same revolutionary movement.[7]