An assistant to self-proclaimed “America’s presidential historian” Barry H. Landau has pleaded guilty to stealing and selling historic documents, including some signed by Abraham Lincoln. Jason James Savedoff, who holds dual Canadian and U.S. citizenship, admitted Thursday in U.S. District Court in Baltimore that he and Landau had stolen documents from numerous museums between December 2010 and July 2011.

Savedoff, 24, who lived with Landau in New York, could receive up to 15 years in prison and fines up to $500,000. He is scheduled for sentencing Feb.10. Landau, 63, is confined to his apartment while awaiting trial. The two men were arrested and indicted in July after Savedoff was seen by an employee of the Maryland Historical Society taking a document from the Baltimore archive. At the time, they were alleged to have with them 60 documents owned by the society.

More than 10,000 documents were seized from Landau’s Manhattan apartment. National Archives employees are cataloging the documents and trying to trace their owners.