Photo of Julio Decker

Dr Julio Decker

MA(Cologne), PhD(Leeds)

  • BS8 1TB


Research output per year

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Personal profile

Research interests

One of my main research interests is the history of race and migration in the United States. My first project analyses the Immigration Restriction League (IRL), a progressive-era lobby group canvassing for the restriction of the so-called new immigration. I show how the IRL transformed abstract ideas about health, criminality, gender, and race into immigration regulations that excluded racialized groups. Apart from investigating links to eugenicists, the Bureau of Immigration, and transnational discourses of whiteness, I my analysis focused on the League's understanding of active citizenship, its role in shaping the modern nation-state, and its significance for American conservatism.

My new project focuses on the history of German and American colonial railroads. I investigate how this new technology reshaped understandings and uses of concepts of space, free and unfree labour, global capitalism and colonial knowledge. I am particularly interested in exchanges and circulations both within and between Empires.


Office 1.H024, 3-5 Woodland Road (new Humanities Building), consultation hours:

(0117) 92 88627,, @drjuliodecker

Research supervision

In the past, I have co-supervised Dr Andrew Primmer's work on the history of Colombian railroads, and am currently co-supervising a project on the history of meteorology in China. My former MPhil students worked on gentrification and LGBTQ+ communities in New York City (Ronan Vivian-Byrne) and neglected histories of unsuccessful colonial ports in China (Robert Nield). I have supervised M.A. dissertations on the history of Scottish railroads and national identity and on torture and the American Empire.

I welcome proposals from students working on global history, colonial history, and the history of capitalism, especially with a focus on the United States and/or Germany. While my work mostly concentrates on the Gilded Age, the Progressive Era and the interwar period, I do welcome proposals on the history of migration, race and resistance, scientific racism and eugenics, the history of technology, as well as imperial history. Please don't hesitate to get in touch if you would like to discuss your research plans.


Currently, I am contributing to the first-year courses The Modern World and The American Century. For third-year students, I also offer a special on American Empire and the Reflective Unit on Capitalism. 

In the past, I have taught on the second-year lecture response units Sixties America and its Aftermath and Strangers in the Land: Making Americans and Becoming American. With Dan Haines, I designed and co-taught a third-year lecture response unit on Colonizing Nature. I also contributed to the first-year lecture outline unit Introduction to the History of the British Empire: Rise, Fall and Legacies.

Background Information

As a Portuguese-born German historian specialized in American history and teaching in the UK, I am particularly interested in transnational and global perspectives. While much of my work is dedicated to the history of ideas and discourses, I connect these more abstract topics to the resulting power relations on the ground. When I am not working, I enjoy shouting at the telly when my team, Werder Bremen, is losing again.

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Research Output


Postgraduate Research Travel Grant

Decker, Julio (Recipient), Oct 2010

Prize: Prizes, Medals, Awards and Grants

Postgraduate travel grant

Decker, Julio (Recipient), Oct 2010

Prize: Prizes, Medals, Awards and Grants

Research Grant

Decker, Julio (Recipient), Apr 2009

Prize: Other distinction


The Rise and Fall of Spatial Orders: Historical Narratives and Geopolitical Imaginaries

Julio Decker (Participant)

30 Sep 20192 Oct 2019

Activity: Participating in or organising an event typesParticipation in conference

'Lines of Power? Railroads and Territoriality in German Southwest Africa, 1884-1914'

Julio Decker (Speaker)

27 Feb 2019

Activity: Talk or presentation typesPublic talk, debate, discussion

Society for the History of Technology Annual Conference

Julio Decker (Participant)

24 Oct 201927 Oct 2019

Activity: Participating in or organising an event typesParticipation in conference

Supervised Work

Capital, Monopoly and Economic Nationalism: A History of British Railways in Colombia, 1902-1930

Author: Primmer, A., 23 Jan 2019

Supervisor: Brown, M. (Supervisor) & Decker, R. J. (Supervisor)

Student thesis: Doctoral ThesisDoctor of Philosophy (PhD)


Gentrification and the Growth and Decline of LGBT Space in New York City

Author: Vivian-Byrne, R., 19 Mar 2019

Supervisor: Cole, T. (Supervisor) & Decker, R. J. (Supervisor)

Student thesis: Master's ThesisMaster of Philosophy (MPhil)


Hopes Unrealised: The minor British treaty ports of Wenzhou and Jiangmen

Author: Nield, R., 23 Jan 2019

Supervisor: Bickers, R. (Supervisor) & Decker, R. J. (Supervisor)

Student thesis: Master's ThesisMaster of Philosophy (MPhil)