Linguistics is the scientific study of language, involving analysis of language form, language meaning, and language in context. Language use was first systematically documented in Mesopotamia, with extant lexical lists of the 3rd to the 2nd Millenia BCE, offering glossaries on Sumerian cuneiform usage and meaning, and phonetical vocabularies of foreign languages. Later, Sanskrit would be systematically analysed, and its rules described, by Pāṇini (fl. 6-4th century BCE), in the Indus Valley. Beginning around the 4th century BCE, Warring States period China also developed its own grammatical traditions. Aristotle laid the foundation of Western linguistics as part of the study of rhetoric in his Poetics ca. 335 BC. Traditions of Arabic grammar and Hebrew grammar developed during the Middle Ages in a religious context like Pānini's Sanskrit grammar.