Philology is the study of language in written historical sources; it is a combination of literary studies, history and linguistics. It is also more commonly defined as the study of literary texts and written records, the establishment of their authenticity and their original form, and the determination of their meaning.
Classical philology is the philology of Greek and Classical Latin. Classical philology is historically primary, originating in Pergamum and Alexandria around the 4th century B.C., continued by Greeks and Romans throughout the Roman and Byzantine Empires, and eventually taken up by European scholars of the Renaissance, where it was soon joined by philologies of other languages both European (Germanic, Celtic, Slavistics, etc.) and non-European (Sanskrit, Persian, Arabic, Chinese, etc.). Indo-European studies involves the comparative philology of all Indo-European languages.
Any classical language can be studied philologically, and indeed describing a language as "classical" is to imply the existence of a philological tradition associated with it.
Because of its focus on historical development (diachronic analysis), philology came to be used as a term contrasting with linguistics. This is due to a 20th-century development triggered by Ferdinand de Saussure's insistence on the importance of synchronic analysis, and the later emergence of structuralism and Chomskyan linguistics with its emphasis on syntax.
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