Professor David Ashworth, a historian at the University of Cambridge, defended his latest book on Thursday against accusations that he plagiarized sections of a 2019 monograph by an independent scholar. The allegations have prompted the university to begin a formal review.

Allegations

The claims first appeared in an article published on July 28 in the journal Historical Review. The article compared passages from Ashworth's 2025 book, "The Iron Century," with those in Samuel Peterson's "Forgotten Empires." Peterson, a scholar without an institutional post, accused Ashworth of using his research without attribution.

According to the journal, more than a dozen passages show "close similarity" in wording and structure. The journal said it had verified the comparison using plagiarism-detection software.

Peterson told the BBC on Wednesday that he was "deeply frustrated" that his work had been used without credit. He said he had contacted Ashworth privately last year but received no response.

Professor's Response

In a statement issued through his solicitors, Ashworth said his work was original and properly sourced. He acknowledged shared subject matter but denied any direct copying.

"The similarities arise from common archival material and established historical methods," the statement said. "It is deeply regrettable that false accusations have been made public without discussion."

Ashworth also said his book includes extensive footnotes and a bibliography listing most of the sources he consulted. He added that he was open to an independent review of the claims.

University Review

The University of Cambridge confirmed on Wednesday that it was examining the case under its procedures for academic misconduct. A spokesperson said the process would be thorough and independent.

The university's rules require that all sources be accurately cited and quoted. In cases of alleged plagiarism, a committee of senior academics examines the evidence and recommends action. Possible outcomes include retraction of the work or disciplinary measures.

Ashworth has been a professor of modern European history at Cambridge for 14 years. He holds tenure and has published three previous books.

Context

Academic plagiarism cases have damaged reputations and careers in recent years. Several universities have introduced training on citation practices to reduce unintentional errors.

Some scholars have voiced support for Peterson, noting that independent researchers are often more vulnerable. Others say the case may involve overlapping use of primary documents rather than deliberate copying.

Peterson said on Thursday he would not comment further until the review is complete. He urged the university to release its findings publicly.

What Comes Next

The university has appointed an independent panel to examine the evidence. It said it aims to conclude its investigation by the end of the autumn term.

Both parties have been asked to submit written submissions. The panel may also consult experts in modern European history and publishing practices.

The outcome will be shared with Ashworth and Peterson. A summary may be published in the university's annual report on research integrity.