A centuries-old overseas letter caught people's eye during a stamp exhibition in Guangzhou to commemorate the Chinese seafarer Zheng He.

　　The one-page letter was sent from Macao on Nov. 5, 1841. It reached its destination of London on March 11, 1842, after traveling via Bombay, India.

　　The trip took 116 days, 10 times the time for the average letter sent overseas today.

　　The rare letter's owner, Zhang Hao, chairman of Guangzhou's parcel study association, said he bought it 20 years ago from an auction house in Portugal for more than US$10,000.

　　The handwriting and postmark on the envelop are still very clear after 160 years.

　　"Experts said the letter was rare and its value should be more than 200,000 yuan (US$24,390) now," he said.

　　A set of commemorative stamps for Zheng by China Post, Hong Kong Post and Macao Post also debuted at the stamp exhibition Tuesday, marking the 600th anniversary of his maritime expedition in the 15th century.

　　It was the fifth stamp release jointly conducted by the three postal administrations.

　　The commemorative package includes three stamps and a stamp booklet.

　　The navigator commanded seven expeditions to the "Western Oceans" on royal orders between 1405 and 1433. His fleet used nautical astronomy and geonavigation to visit more than 30 countries and regions in Asia and Africa, extending Chinese cultural and technological influence as well as fostering trade and goodwill.