Chinese writing evolved during the Zhou dynasty with bronze script (1400-700 BCE), inscriptions cast on ritual bronze vessels that became increasingly standardized. Two forms of seal script emerged: large seal script (dazhuan, 1000-200 BCE) appearing on bronze vessels and stone inscriptions, and small seal script (xiaozhuan), standardized by Qin emperor's minister Li Si in 221 BCE. Bronze script maintained pictographic elements while seal script became more abstract and uniform. This evolution paralleled political changes from fragmented Zhou states to unified Qin empire, with writing systems reflecting broader cultural and administrative developments.