It features abstract animal designs under the mouth and eave tile-shaped patterns on the waist.

An inscription was cast into the interior of the vessel, meaning "crafted by Xingshu of the Feng State, dedicated to his wife Boji, a treasure for all his generations to come''.

The Zhou Dynasty developed the practice of inscribing vessels, and such vessels are highly prized. The inscriptions were meant to communicate the owners' political and social achievements to their ancestors and for future generations to see.

Historians believe inscriptions are the single-most striking feature of the Zhou bronzes and were assiduously studied by later generations.

After it was stolen in 1984, China had never given up looking for it over the past 40 years, according to China's Deputy Minister of Culture and Tourism Li Qun.

"Raymond King and his mother resolutely decided to do the right thing. They agreed to unconditionally return the artifact to the Chinese government, an act that is truly admirable," Li said in a video message played at the repatriation ceremony held at the Portland Art Museum last month.

Also commendable was the international cooperation and a shared appreciation for the human cultural heritage, said Li, who is also the director of China's National Cultural Heritage Administration.