The Abraham Lincoln Presidential Library and Museum has received a ring that once belonged to the 16th president's youngest son.
The Springfield museum says the ring was a gift from an Illinois family.
It is made of braided hair from Thomas "Tad" Lincoln's pony, and has a small clasp engraved with "Thomas Lincoln."
Museum officials say Thomas Lincoln used to ride his pony near the White House. In the 1860s he gave the ring to the wife of a Union officer who was stationed nearby. The woman later moved to Effingham, Illinois.
Her descendants kept the ring until the family recently donated it to the museum.
Museum curator James Cornelius calls the ring "an amazing and personal piece."