The Presidential Building, also known as "Zichao House" and the Concrete House, was one of the most important buildings in the complex. Situated on the northernmost part in the palace, the six-storey house with the structure of reinforced concrete was one of the tallest buildings in Nanking in the 1930s. The construction started in 1934, and finished in December 1935. Lin Sen used this house as the office of Chairman of the Nationalist Government until the Japanese troops captured Nanking. From 1940 to 1945, this Japanese-occupied house was converted into the office of the Legislative Yuan and the Control Yuan of the Reorganized National Government. In 1946, Chiang's Nationalist Government re-took Nanking, then used this house as the office of the Nationalist Government for the second time. After the presidential inauguration ceremony in 1948, it became the seat of the president of the ROC. In April 1949, the People's Liberation Army took control of this house. The house lost the position of the president's seat from then on. From December 1949, the Presidential Office Building of Taipei has become the seat of the ROC president. In Mainland China, Zhongnanhai became the seat of the central government and the official residence of the Leader of the Communist Party of China since October 1949.