By the late 12th century, many critics of the examination system and government-run schools initiated a movement to revive private academies. During the course of the Southern Song, the academy became a viable alternative to the state school system. Even those that were semi-private or state-sponsored were still seen as independent of the state's influence and their teachers uninterested in larger, nationwide issues. One of the earliest academic institutions established in the Song period was the Yuelu Academy, founded in 976 during the reign of Emperor Taizu (r. 960–976). The Chinese scientist and statesman Shen Kuo was once the head chancellor of the Hanlin Academy, established during the Tang dynasty. The Neo-Confucian Donglin Academy, established in 1111, was founded upon the staunch teaching that adulterant influences of other ideologies such as Buddhism should not influence the teaching of their purely Confucian school. This belief hearkened back to the writings of the Tang essayist, prose stylist, and poet Han Yu (768–824), who was certainly a critic of Buddhism and its influence upon Confucian values. Although the White Deer Grotto Academy of the Southern Tang (937–976) had fallen out of use during the early half of the Song, the Neo-Confucian philosopher Zhu Xi (1130–1200) reinvigorated it.