Da Tang Lotus Garden

Yang Gui Fei was one of the Four Great Beauties of ancient China. This drama centers around the ups and downs of her love life, the most well-known part of which was shared with Emperor Xuan Zong during the later years of his reign. Yang Gui Fei's real name was Yang Yu Huan and she was originally betrothed and married to Prince Shou, one of Xuan Zong's numerous sons. However, when Xuan Zong saw her, he fell head over heels in love and forced her to divorce Prince Shou. Later he took her as his own imperial consort, thus the name "Yang Gui Fei".
Although he was a competent emperor at one time, Xuan Zong's obsession with Yang Gui Fei caused him to neglect court affairs. This eventually led to a power struggle for central control of the government involving An Lu Shan and Yang Guo Zhong, both of whom had gained favor and power due to Yang Gui Fei's influence. The consequences were dire, and Yang Gui Fei was blamed for the rebellion, forcing Xuan Zong to make a painful decision...
(Source: Lady Zhuge at D-addicts)