In his seminal essay ‘The Myth of the English Reformation’, Diarmaid MacCulloch observed ‘that the issue of continuity is as much theological as historical; certainly, at the present day, it lies at the heart of some of the most serious theological debates within the Anglican Communion’. In the thirty years since that article was published, debates about the nature, identity and authority of the Anglican Communion have only intensified, with questions about doctrinal continuity and fidelity assuming increasing prominence. Ashley Null has examined the ways in which the theological inheritance of what he terms ‘Reformation Anglicanism’ has acquired a new traction in the Anglican Communion in the present day, particularly in various provinces in the Global South. Null has demonstrated that these various appeals to the sixteenth-century formularies are themselves diverse and contested, offering competing accounts of what fidelity to that tradition looks like. The primary focus of this essay is on theological questions, rather than strictly historical ones, albeit theological questions considered in historical and historiographical perspective. It makes two central claims: first, that the contested nature of England’s Reformation was written into the early coding of what became the worldwide Anglican Communion; and second, that the nature of ‘orthodoxy’ – not simply which beliefs or practices might (or might not) be understood as ‘orthodox’ – has become contested theological and ecclesiological ground in twenty-first-century global Anglicanism.