A state seal used during the Joseon Dynasty over 100 years ago is currently on display in Seoul.

The National Palace Museum put the seal on display Tuesday after having purchased it from a foreign collector late last year as part of its program to retrieve overseas Korean cultural assets.

The seal, adorned with a crimson decorative tassel, was used by Emperor Gojong for secret diplomatic documents in the later years of his rule.

The 4.8-centimeter-wide, 794-gram seal has a turtle-shaped handle and is inscribed with the words "Emperor's Seal."

According to the museum, the seal, which was in actual use during the reign of the Korean king, is the first of its kind to be displayed.

Other kings' seals currently displayed at domestic museums were all made following the deaths of the kings.