The most popular of Dragon Boat Festival is in commemoration of Qu Yuan (340-278 BC). 

Who is Qu Yuan? -- He was minister of the State of Chu and one of China´s earliest poets.

What did he do?

Statesman -- In face of great pressure from the powerful Qin State, he advocated enriching the country and strengthening its military forces so as to fight against the Qin.

Poet -- He composed immortal poems including Li Sao (The Lament), Tian Wen (Heavenly Questions) and Jiu Ge (Nine Songs), which had far-reaching influences.

What happend to him at last?

-- In 278 BC, he heard the news that Qin troops had finally conquered Chu´s capital, so he finished his last piece Huai Sha (Embracing Sand) and plunged himself into the Miluo River, clasping his arms to a large stone.