The Royal Seal of King Deokjong is seen at a return ceremony held in Seoul, April 1, 2015. [Photo/IC]

The Cultural Heritage Administration of South Korea(CHA) and SAM has discussed the seal's return from July to November in 2014. The two sides made joint announcement on the agreement of the seal's return to South Korea in December, 2014. SAM voluntarily determined to return not only the seal to South Korea, but also a silk cord crafted by Kim Eun-Young, an important Seoul city cultural asset.

The CHA said this agreement between the CHA and SAM was made possible by ongoing discourse based on mutual respect and trust together with cultural understanding, as royal seals are a precious element of cultural heritage that symbolize the national dignity and pride of the people of South Korea.

It was reported that many Korean ancient royal seals and other objects of cultural heritage have been transferred from the Korean peninsula to overseas countries during the Korean War.

Kimerly Rorschach, director and CEO of SAM, said the SAM didn't know the history before Stimson bought the seal from the art dealer. But knowing that the seal was likely came out of South Korea in the same way, they all agreed that it was right and important to return it to South Korea as an important cultural heritage.

Last April, US President Obama also returned nine ancient royal seals taken by a US soldier during the Korean War six decades ago during his visit to South Korea.