Emperor Yang of Sui - As Crown Prince

As Crown Prince

It is widely believed that Yang Guang also continued to scheme to secure his status as the crown prince. Such commonly believed tales include the followings.

By 602, His brother, Yang Xiu the Prince of Shu, who, was commandant of Yi Province (益州, roughly modern Chengdu, Sichuan), and had great resources at his disposal. Yang Guang collected evidence of Yang Xiu's wrongdoing, particularly wastefulness, and had Yang Su submit them to Emperor Wen. Emperor Wen summoned Yang Xiu back to the capital and had Yang Su investigate, and both Yang Guang and Yang Su further manufactured evidence against Yang Xiu. Emperor Wen reduced Yang Xiu to commoner rank and put him under house arrest.

Also in 602, Empress Dugu died. It was said that Yang Guang pretended to mourn greatly, refusing most foods, but in private continued to dine normally.

In 604, while Emperor Wen was at his vacation palace Renshou Palace (仁壽宮, in modern Baoji, Shaanxi), he fell ill and then died—a death, however, that traditional historians, while admitting a lack of direct evidence, believed to be a murder ordered by Yang Guang (see below). Yang Guang, after sending Yang Yue to kill Yang Yong, announced Emperor Wen's death and took the throne as Emperor Yang.