Reunified Chinas Tang Dynasty (618-907) high culture set a high point for many things, including poetry. Various schools of Buddhism (a religion from India) flourished as represented by the Chinese Chán (or Zen) beliefs of Wang Wei (Tang dynasty) (701-761). His quatrains (jueju) describing natural scenes are world-famous examples of excellence, each couplet conventionally containing about two distinct images or thoughts per line. Tang poetrys big star is Li Bai (701-762) also pronounced and written as Li Bo, who worked in all major styles, both the more free old style verse (Gushi (poetry)) as well as the tonally regulated new style verse (Regulated verse). Regardless of genre, Tang poets notably strove to perfect a style in which poetic subjects are exposed and evident, often without directly referring to the emotional thrust at hand. The poet Du Fu (712-770) excelled at regulated verse and use of the seven-character line, writing denser poems with more allusions as he aged, experiencing hardship and writing about it. A parade of great Tang poets also includes Chen Ziang (661-702), Wang Zhihuan (688-742), Meng Haoran (689-740), Bai Juyi (772-846), Li He (790-816), Du Mu (803-852), Wen Tingyun (812-870), (listed chronologically) and Li Shangyin (813-858), whose poetry delights in allusions that often remain obscure, and whose emphasis on the seven-character line also contributed to the emerging posthumous fame of Du Fu, now ranked alongside Li Bai. The distinctively different Ci (poetry) poetry form began its development during the Tang as Central Asian and other musical influences flowed through its cosmopolitan society.
Question: How many years old was poet Du Fu at the time of his death?
Answer: 58