The practice of burying relics in sets of containers made of precious materials is mentioned in the earliest Indian Buddhist texts. The practice spread to China in the seventh and eighth centuries. Important relics was distributed in order to propagate Buddhism and further unify the nation. The relics could be placed within a gold container which in turn was enclosed in a silver container which was then placed inside a larger bronze casket. Eventually further and other materials was used, the outermost maybe of stone or pottery. The nestled ensemble was then buried with great ceremony, .