{"id":4996,"date":"2026-09-30T06:00:54","date_gmt":"2026-09-30T13:00:54","guid":{"rendered":"https:\/\/bartbaggett.com\/blog\/?p=4996"},"modified":"2026-09-24T09:45:45","modified_gmt":"2026-09-24T16:45:45","slug":"joseph-cosey-lincoln-forgery","status":"publish","type":"post","link":"https:\/\/bartbaggett.com\/blog\/joseph-cosey-lincoln-forgery\/","title":{"rendered":"Joseph Cosey: The Forger Who Fooled Collectors with “Lincoln” Letters"},"content":{"rendered":"

In 1929, a man named Martin Coneely walked into the Library of Congress and asked to see some old documents. He left with something remarkable\u2014a pay warrant from 1786 signed by Benjamin Franklin. Coneely tried to sell it to a New York dealer, who promptly declared it a fake. It wasn\u2019t. But that moment changed everything for Coneely, because he realized something crucial: the people buying historical documents often couldn\u2019t tell the difference between real and forged.<\/p>\n

Joseph Cosey, born Martin Coneely, spent two decades forging letters and documents in the names of Abraham Lincoln, Benjamin Franklin, and others. His work fooled collectors and still circulates, now openly labeled as forgeries. Experts spot fakes not by one dramatic test, but by careful comparison of habits and details.<\/p>\n

\"Illustration
Illustration: Abraham Lincoln beside a forged letter and magnifier, with details from the Joseph Cosey case. Not a reproduction of the original document.<\/figcaption><\/figure>\n

The Making of America\u2019s First Convicted Forger<\/h2>\n

After that pivotal encounter, Coneely reinvented himself as Joseph Cosey. He became notorious for his skill in imitating the handwriting and style of famous Americans. He didn\u2019t just copy signatures\u2014he produced entire letters, legal briefs, and manuscripts. His subjects ranged from Abraham Lincoln and George Washington to Edgar Allan Poe and Thomas Jefferson. Among his most audacious creations were a supposed “draft” of the Declaration of Independence in Jefferson\u2019s hand and the “manuscript” of Poe\u2019s The Black Cat<\/em>.<\/p>\n

Cosey was methodical. He sourced genuinely old paper, sometimes centuries old. He mixed his own iron-gall ink to match what would have been used in the 18th or 19th centuries. For nearly twenty years, his forgeries made their way into collections, museums, and auction houses.<\/p>\n

How Cosey\u2019s Forgeries Fooled\u2014and Failed<\/h2>\n

Joseph Cosey\u2019s Lincoln letters were especially convincing. According to a 1956 New Yorker<\/em> profile, he “papered the country” with so many Lincoln forgeries that the autograph market never fully recovered. Some of his fakes are still believed to be in collections today, catalogued as real.<\/p>\n

But even the best forger leaves traces. Cosey\u2019s attention to detail often stopped at the main signature. When a document required a second signature\u2014a clerk\u2019s countersignature\u2014he rarely matched the real clerks\u2019 handwriting or names. His Franklin signatures sometimes mimicked Franklin\u2019s style from a decade too early for the supposed date. The more you compare, the more the forger\u2019s own habits start to show through.<\/p>\n

Eventually, Cosey was caught. He was arrested in 1937, served about a year in prison, and reportedly returned to forgery after his release. He continued his work into the 1940s and died around 1950. Today, auction houses like RR Auction and Bonhams sell known Cosey forgeries as their own category\u2014labeled, and fetching a few hundred dollars each.<\/p>\n

How Document Examiners Spot a Forgery<\/h2>\n

In my experience as a forensic document examiner, forgery detection is rarely about a single dramatic test. It\u2019s about habits. No one writes exactly the same way twice, and no two people write exactly alike. A skilled forger can copy the shape of a letter, but the underlying rhythm, pressure, and natural variation are much harder to fake.<\/p>\n

When examining a questioned document, I look for:<\/p>\n