Query: When was the site believed to be ancient city of Shu discovered, and by whom?
Context: The existence of a highly developed civilization with an independent bronze industry in Sichuan eventually came to light with an archaeological discovery in 1986 at a small village named Sanxingdui in Guanghan, Sichuan. This site, believed to be an ancient city of Shu, was initially discovered by a local farmer in 1929 who found jade and stone artefacts. Excavations by archaeologists in the area yielded few significant finds until 1986 when two major sacrificial pits were found with spectacular bronze items as well as artefacts in jade, gold, earthenware, and stone.