The Londoner John Blackwell (1624-1701), shaped by his parents’ Puritanism and merchant interests of his iconoclast father, became one of Oliver Cromwell’s New Model Army captains. Working with his father in Parliament’s financial administration both supported the regicide and benefitted financially from the subsequent sales of land from those defeated in the civil wars. Surviving the Restoration, Blackwell pursued interests in Ireland and banking schemes in London and Massachusetts, before being governor of Pennsylvania. Blackwell worked with his son, Lambert Blackwell, who established himself as a merchant, financier and representative of the state in Italy during the wars of William III before being embroiled in the South Sea Bubble. The linked histories of the three Blackwells reinforce the importance of kinship and the development of the early modern state centred in an increasingly global London and illustrate the ownership of the memory of the civil wars, facilitated by their kin links to Cromwell and John Lambert, architect of Cromwell’s Protectorate, by those who fought against Charles I. Suitable for specialists in the area and students taking courses on early modern English, European and American history as well as those with a more general interest in the period.