Staff from the Palace Museum clean a chair in the Yangxin Dian, June 11, 2016. [Photo/Xinhua]

The Palace Museum, also known as the Forbidden City, has begun to renovate one of its major former imperial courtyard houses in an effort to better protect a building that is nearly 500 years old and to set an example for preserving other historical buildings.

The Yangxin Dian, or the Hall of Mental Cultivation, built in 1537, hasn't been renovated in around 35 years. It is expected to be reopened in 2020 with 1890 ancient cultural artifacts on exhibition.

The courtyard compound was the residence of eight emperors in the Qing Dynasty (1644–1911), where they managed state affairs and received senior officials.

The museum director Shan Qixiang said, "As a pivotal place for the former Qing authorities, the heritage has enormous historical value with the finest Chinese paintings, collections of ancient books and decorations of bronzes, porcelain and jade."

He elaborated on the comprehensive plan for the three-year renovation project on Monday saying the trailblazing work was undertaken after a year of thorough investigation into the history and culture of the heritage.

"The renovation is divided into 33 sub-projects, including preserving the building itself, setting up a database for the collections in the compound, and researching on the major historical events associated with the architecture," he said.

According to previous media reports, 220 million yuan ($33 million) is slated for the renovation project. The funds were mostly from donations.