I am an assistant professor in the Department of History and Art History at George Mason University, working on the history of American religions as a digital historian. I write regularly on my own blog and for the Religion in American History group blog.

I am currently working on a book manuscript titled The Chance of Salvation: A History of Conversion in America. This book is a history of conversions between religions in the nineteenth-century United States. It describes how the nature of religious identity in the United States changed over the course of the nineteenth century due to conversion, as more people came to conceive of their religion as an identity they had chosen rather than one they had inherited.

Digital Projects

America’s Public Bible thumbnail

America’s Public Bible

Biblical quotations in U.S. newspapers during the nineteenth and early twentieth centuries.

The Spread of U.S. Slavery, 1790–1860 thumbnail

The Spread of U.S. Slavery, 1790–1860

Maps of enslaved and free African Americans before the Civil War.

Bibliography of Urban American Religious History thumbnail

Bibliography of Urban American Religious History

An interactive bibliography of books about religion in U.S. cities.

Spatial Humanities Workshop thumbnail

Spatial Humanities Workshop

Workshop materials on mapmaking and spatial humanities for research and teaching.

Gender Predictor thumbnail

Gender Predictor

Predict your gender from your first name and birth year using historical data.

Divergence in Sex Ratios, 1820–2010 thumbnail

Divergence in Sex Ratios, 1820–2010

Counties that were disproportionally male or female over time, based on U.S. Census data.

Paulist Missions, 1851–1906 thumbnail

Paulist Missions, 1851–1906

Locations and statistics of missions preached by the Paulist Fathers during the nineteenth century.

Historical Boundaries of the U.S. thumbnail

Historical Boundaries of the U.S.

The political boundaries of the United States on each date from 1783 to 1912.

The American Converts Database thumbnail

The American Converts Database

A database of converts and conversions in American religious history.

Digital History Methods in R thumbnail

Digital History Methods in R

Book in progress on using R to do digital history.

Worksheets for Historical Data Analysis with R thumbnail

Worksheets for Historical Data Analysis with R

Worksheets for learning historical data analysis in R by example.

Other projects

Detecting Text Reuse in Nineteenth-Century Legal Documents (ongoing)

Historical Demographics of U.S. Religion (ongoing)

Analyzing Historical History Dissertations (2014)

Journal of Southern Religion (2011–2015)


Journal articles

Cameron Blevins and Lincoln Mullen, “Jane, John … Leslie? A Historical Method for Algorithmic Gender Prediction,” Digital Humanities Quarterly, 9, no. 3 (2015). web

“Lynching, Visualization, and Visibility,” Journal of Southern Religion 17 (2015). web

“The Contours of Conversion to Catholicism in the Nineteenth Century,” U.S. Catholic Historian 32, no. 2 (2014): 1–27. DOI: 10.1353/cht.2014.0007, Project Muse, PDF

“Using Metadata and Maps to Teach the History of Religion,” Transformations: The Journal of Inclusive Scholarship and Pedagogy, 24, no. 3 (2014): 34–40. PDF preprint

“Confessionalization and the Creedal Tradition,” The Proceedings of the South Carolina Historical Association (March 2010): 79–90. PDF

Book chapter

“Digital Humanities Is a Spectrum; or, We’re All Digital Humanists Now,” in Melissa Terras, Edward Vanhoutte, and Julianne Nyhan, eds., Defining Digital Humanities: A Reader (Ashgate, 2013). web

Edited sources

“A Narrative of the Troubles in the Second Church in Windsor, 1735–1741,” by Roger Wolcott, Journal of Jonathan Edwards Studies 2, no. 2 (2012): 83–142. web, PDF

Academic Software

textreuse: Detect Text Reuse and Document Similarity

tokenizers: Tokenize Text

gender: Predict Gender from Names Using Historical Data

internetarchive: Search the Internet Archive, retrieve metadata, and download files

USAboundaries: Historical Boundaries of the United States of America, 1629-2000

historydata: Data Sets for Historians

omekaR: A client for the Omeka API

mullenMisc: An R package of functions I use across projects

Catalog Search: Searches other catalogs for records related to Omeka items

Honor Thy Contributors: An Omeka plugin to give credit to contributors to your Omeka site

jekyll_figure: Detect Text Reuse and Document Similarity

bibkeys: Utility to list all the citation keys in a BibTeX file

omeka_client: A client for the Omeka API

jekyll-ebook: Generate an EPUB e-book from Jekyll posts and pages


Text Analysis for Historians (fall 2016)

Data and Visualization in Digital History (spring 2016)

Religion and Capitalism in the US (spring 2015)

The Digital Past (spring 2015)

Programming in History/New Media (fall 2014)

Church and State in America (fall 2014)

Mapping Boston’s Religions (spring 2014)

Religious Pluralism and the American State (fall 2012)


Kellen Funk and Lincoln Mullen, “Text Reuse for Digital Legal History.” To be given at the American Society for Legal History, Toronto, Canada, October 27, 2016.

Jason Heppler and Lincoln Mullen, “R, Interactive Graphics, and Data Visualization for the Humanities.” To be given at Digital Humanities Summer Institute, University of Victoria, British Columbia, Canada, June 6–10, 2016.

Data Visualization Workshop.” Given at the University of Helsinki, Finland, December 16–18, 2015.

Spatial Humanities Workshop.” Given at Concordia College, Moorhead, MN, June 1–5, 2015.

“Introduction to Mapping and Spatial History.” Given at Doing Digital History, NEH-ODH Summer Institute, George Mason University, August 11, 2014. (slides and notes)

Data Analysis for Humanists.” Given at THATCamp American Historical Association 2014, Washington, January 5, 2014, and THATCamp American Academy of Religion 2013, Baltimore, November 22, 2013.

How to Use a Database for Historical Research.” Given at THATCamp New England 2013, University of Connecticut at Storrs, October 18, 2013.

The Humanist’s Operating System; or, Scholarship in Plain Text.” Given at THATCamp New England 2012, Brown University, October 20, 2012.