He walked into the river a frustrated and depressed man, enraged by the corruption at court and his helplessness in correcting the situation. Qu Yuan, patriot, poet and exiled minister of the Chu State during the Warring States Period (475-221 BC), marked the fall of his country by committing suicide.
Before he died, he had walked among his people, collecting folklores, songs and odes. He also produced some great poetry reflecting his life and turbulent times.
Qu Yuan was much loved by the common folk, and they honored him by creating a festival around the anniversary of his death. They had row-boat contests, and they wrapped rice in bamboo leaves which they threw into the river - presumably so the water creatures would be distracted by the free food, and spare the poet's body.
That was more than 2,000 years ago.
These days, the festivities still commemorate Qu Yuan, and his name comes up again every year as all Chinese celebrate Duanwu on the fifth day of the fifth lunar month. It is also the height of summer, and several traditions have evolved around that.