Classical Chinese is the written literary language used across China from roughly the Warring States period through the early twentieth century, based grammatically on the spoken Chinese of the Zhou dynasty's later centuries but increasingly diverging from spoken vernacular Chinese over the subsequent two millennia, functioning much like Latin in medieval Europe as a stable, prestige literary standard largely detached from everyday speech.
Classical Chinese belongs to the Sinitic branch of the Sino-Tibetan language family, and its extremely terse, allusive grammar, often omitting explicit subjects and relying heavily on context, produced a distinctive commentary tradition in which later scholars wrote extensive explanatory glosses on canonical texts to clarify meanings that later readers could no longer parse without assistance.
Classical Chinese carries the entire foundational canon of Confucianism, including the Analects attributed to Confucius and the other Four Books and Five Classics that structured Chinese education and civil service examinations for centuries, as well as core Taoist texts including the Tao Te Ching attributed to Laozi and the Zhuangzi, and the Chinese Buddhist canon, translated into Classical Chinese from Sanskrit and other source languages beginning in the first centuries CE.