One encounters some of the most interesting figures of history while venturing down the bypaths of one's researches. I found one such while cutting through the thickets of seventeenth-century Dutch history. Lieuwe van Aitzema is hardly unknown to specialists, to be sure, but he has been for them little more than a richly informed chronicler, if one whose pen was dipped in the acid of total cynicism. How that attitude squared with his apparent conversion to Catholicism late in life has been a puzzle ever since the sources indicating his change of religion were discovered a few decades ago. Historians of the Cromwellian regime have long known some of his work but not the man himself, for his secret dispatches from The Hague that are printed in John Thurloe's Collection of State Papers are without his signature. As for historians of the Dutch Republic, they can do no work on the middle decades of the seventeenth century without drawing upon Aitzema's Saken van Staet en Oorlogh (‘Affairs of State and War’) as their fullest and best contemporary printed source. Yet, within the pages of that work, scattered in the midst of documents printed in extenso and arid, if highly useful detailed accounts of events, are to be found commentaries of great pungency and highly personal character on history, politics and religion. It is Aitzema's mind as revealed in these obiter dicta which is the object of my attention in these pages.