A New History of Early Christianity by Charles Freeman Against the conventional narrative of the inevitable "triumph" of a single distinct Christianity, Freeman shows that there was a host of competing Christianities, many of which had as much claim to authenticity as those that eventually dominated. Online available.

Landmarks in the history of early Christianity by Kirsopp Lake Lectures given in 1919. Dated, but classic. Online available.

Early Christianity : origins and evolution to AD 600 by Ian Hazlett Online available.

The Rise of Western Christendom : triumph and diversity, A.D. 200-1000 by Peter Brown Christianity's first thousand years of history. fully updated bibliography and index

Writing the History of Early Christianity by Markus Vinzent poses radically new questions on the famous 'Abercius' inscription, on the first extant apologist Aristides of Athens, on the prolific Hippolytus of Rome, and on Ignatius and the first non-canonical collection of letters. methodology of a retrospective writing. Online available.

The Rise of Christianity Through the Eyes of Gibbon, Harnack and Rodney Stark by Jan N. Bremmer locates their concerns and explanations within their own times, discussing their analyses and approaches. Online available.