The historian Andrew Porter, who has died aged 75 after suffering from Parkinson’s disease, put religion back into analyses of British imperialism at a time when they were more often focused on secular dynamics.
In his book Religion Versus Empire? British Protestant Missionaries and Overseas Expansion, 1700-1914 (2004), he emphasised the extent to which the growth of empire was accompanied by an equally extensive Protestant missionary movement. Porter took seriously both the domestic British context and missionaries’ theological commitments in describing the interactions of mission and imperialism, never blurring the distinction between the two.
To see missionaries as instruments of imperial expansion or agents of a cultural imperialism struck him as simplistic. While acknowledging that the growth of Protestant overseas missions and the expansion of empire were connected, he demonstrated that missionaries and colonial authorities were frequently at odds.
By comparison with their Iberian Catholic predecessors, Porter argued that British Protestant missions had a stronger sense of their independence from the state, even though they sometimes sought its support. The British government itself worried that evangelical overseas missions might undermine empire, for example through the content of missionary education or evangelising in Islamic areas.
In shaping an aspect of the history of empires hitherto dominated by regional or denominational case studies, he inspired a generation of younger scholars to make their own contributions to a broader conception of the field.

Photograph: Alpha Historica/Alamy
Porter’s work on religion and empire represented a departure from his earlier research on southern Africa. His first book, The Origins of the South African War (1980), offered a political explanation of the conflict, exploring how the colonial secretary, Joseph Chamberlain, mobilised British public opinion to support the cause of uitlanders – in Boer terms, foreigners, mainly British, denied political rights in the Boer republic of the Transvaal.
This interpretation led him to engage in characteristically robust, but always courteous, exchanges with those holding different views, in this case with those who saw the war as the product of economic forces.
In the mid-1990s he similarly became a prominent protagonist in the debates provoked by Peter Cain and AG Hopkins’s “Gentlemanly capitalism” thesis, which identified a nexus of City financiers and landowning families as the key influence on imperial policy over several centuries.

Another new focus was the end of empire, then just emerging as a rapidly developing area within imperial history, to which Porter and AJ Stockwell contributed an important collection of documents exploring British Imperial Policy and Decolonisation (1987).
For Porter, the historical profession was never just about lone scholarship, and he was in various ways involved in publishing 18 volumes on British Documents on the End of Empire; the Oxford History of the British Empire, notably as editor of volume 3 on The Nineteenth Century (1998); the Oxford Dictionary of National Biography, as an associate editor; and the monumental Royal Historical Society Bibliography of Imperial, Colonial and Commonwealth History Since 1600 (2002), as editor. He was also co-editor for 11 years of the Journal of Imperial and Commonwealth History.
Through these endeavours, Porter, along with his American colleague Wm Roger Louis, sought, perhaps more than any others of their generation, to give leadership to a field challenged by the rise of area studies and later reinvigorated, but also disrupted, by the emergence of a “new” imperial history, characterised by a greater focus on culture, discourse and gender, as well as on the ways in which Britain itself was constituted by involvement in empire.
Porter’s scepticism about some of the new approaches made him determined to defend the space for studies which exemplified the best of more traditional approaches.

He nevertheless remained keen to learn from others’ work, not least at weekly Imperial History seminars at the Institute of Historical Research. He also served as honorary secretary of the Royal Historical Society and chair of the Institute of Commonwealth Studies, and was an active member of the History at the Universities Defence Group.
Born in London, Andrew was the son of Peter Porter and his wife, Betty (nee Luer). The family moved to Chester, where Peter was cathedral secretary, Andrew sang in the cathedral choir and Betty was a college administrator. From the choir school, Andrew went on a scholarship to Christ’s Hospital school, Horsham, West Sussex, and while there became a violinist in the National Youth Orchestra.
At St John’s College, Cambridge, he switched from geography to history, and led the university’s various orchestras. He was a keen string quartet player, not least with his wife, Mary Faulkner, a music teacher, whom he married in 1972, and with whom he had two sons, Matthew and Simon.
After completing his PhD at Cambridge, in 1970 he went to Manchester University as a lecturer, moving to King’s College London the following year. He became professor in 1990, and three years later Rhodes professor.
A long-serving and effective head of the history department, he took early retirement in 2008 after his Parkinson’s diagnosis. Together with Mary he participated in the vibrant musical life of Clun, in the Shropshire Hills, giving his last violin recital in 2013.
He is survived by Mary, his sons and two grandsons.
• Andrew Neil Porter, historian, born 12 October 1945; died 4 March 2021