Ascending Mount Yangtai was consecutively owned by royal courts since the Northern Song Dynasty (960-1127) until it left the Forbidden City, with the end of monarchy in China.

In 1937, during the War of Resistance Against Japanese Aggression (1931-45), many precious treasures were sold abroad. But Zhang spent a huge sum of money to buy Ascending Mount Yangtai and several other works from another collector. Another exhibit, Palace Entertainers in the Kingdom of Shu, a Ming Dynasty (1368-1644) painting by Tang Yin depicting court life in a 10th-century kingdom in today's Sichuan province, was among the works purchased by Zhang at the time.

"It has abundant color, but the painting doesn't lose its elegance for natural transition and comparison of the colors," Hao Yanfeng, an associate researcher of ancient calligraphy and painting at the Palace Museum, says while introducing the piece to visitors.

In the late 1940s, Zhang made plans for the Palace Museum to purchase some former royal collections, and helped bargain to get them back at lower prices.

After the founding of New China in 1949, Zhang kept donating his collections to public institutions in the country. In 1956 alone, Zhang donated eight key calligraphy works and paintings to the Palace Museum. He gave Ascending Mount Yangtai to Chairman Mao Zedong's office, and Mao transferred it to the museum in 1958, bringing the lost treasure back to the Forbidden City's premises.

According to Shan, nearly 20,000 cultural relics were donated to the Palace Museum by 330 individuals in the 1950s. He says Zhang had set a good example.

Hao recommends several other key masterpieces among Zhang's donations in the 1950s, which are also on display in Beijing.