WBEZ Chicago reports that the Abraham Lincoln Presidential Library Foundation sought national museum experts’ review in 2013 and an FBI DNA analysis in 2015 to prove Lincoln’s link to the iconic hat. Neither turned up sufficient evidence it belonged to the 16th president.

The hat is the $6.5 million jewel of the foundation’s $25 million acquisition of Lincoln-related artifacts in 2007. The foundation still owes $9.7 million on a loan used to buy the collection and has begun preparations to auction some items .

Provenance had been based on a 1958 affidavit from a descendant of a farmer who said Lincoln gave him the hat in 1861.