In the last forty years the accepted portrait of the parliamentarian party during the Great Civil War has changed almost beyond recognition. A score of books and articles have been devoted, with much debate, to reinterpreting the nature of the factions comprising that party. By contrast, the accepted view of its opponent, the royalist party, is still that established by Gardiner over a hundred years ago. This situation is not unduly surprising. Some of the principal sources for a study of the royalist party, such as the journals of the royalist parliament, were destroyed at the end of the war. Furthermore, the royalists may seem ultimately less significant objects of study than their rivals, in that they lost the war and therefore contributed nothing, save as a menace, to the subsequent formation of English polity and the making of the modern world. Though not surprising, such an attitude is none the less indefensible. Considerable material for such a study does survive. Clarendon's comments, whether in his History1 or his Life2, are well known. By contrast other retrospective sources, notably Prince Rupert's ‘Diary’, a summary of his career by an unknown admirer,3 are almost unused. These may be compared with the contemporary evidence of hundreds of letters preserved in the British Library, Bodleian Library and local record offices. In favour of such a study, it may be argued that until the royalist party is understood the nature of the Great Civil War cannot be properly appreciated. Moreover, the significance of the parliamentarian victory for a future England is only clear if some suggestion can be made of the possible consequences of a royalist triumph.