City and County of Cardiff: History
=== Etymology ===
Caerdydd (the Welsh name of the city) derives from the Middle Welsh Caerdyf. The change from -dyf to -dydd shows the colloquial alteration of Welsh f [v] and dd [ð] and was perhaps also driven by folk etymology. This sound change probably first occurred in the Middle Ages; both forms were current in the Tudor period. Caerdyf has its origins in post-Roman Brythonic words meaning "the fort of the Taff". The fort probably refers to that established by the Romans. Caer is Welsh for fort and -dyf is a form of Taf (Taff), the river which flows by Cardiff Castle, with the ⟨t⟩ showing consonant mutation to ⟨d⟩, as is normal in compound words, and the vowel showing affection as a result of a (lost) genitive case ending.
The anglicised Cardiff is derived from Caerdyf, with the Welsh f [v] borrowed as ff , as also happens in Taff (from Welsh Taf) and Llandaff (from Welsh Llandaf).
The antiquarian William Camden (1551–1623) suggested that the name Cardiff may derive from *Caer-Didi ("the Fort of Didius"), a name supposedly given in honour of Aulus Didius Gallus, governor of a nearby province at the time when the Roman fort was established. Although some sources repeat this theory, it has been rejected on linguistic grounds by modern scholars such as Professor Gwynedd Pierce.
Archaeological evidence from sites in and around Cardiff show that people had settled in the area by at least around 6000 BC, during the early Neolithic: about 1,500 years before either Stonehenge or the Great Pyramid of Giza was completed. These include the St Lythans burial chamber near Wenvoe, (approximately four miles or six km west of Cardiff city centre); the Tinkinswood burial chamber, near St. Nicholas (about six miles or ten km west of Cardiff city centre), the Cae'rarfau Chambered Tomb, Creigiau (about six miles or ten km northwest of Cardiff city centre) and the Gwern y Cleppa long barrow, near Coedkernew, Newport (about eight miles or thirteen km northeast of Cardiff city centre). A group of five Bronze Age tumuli is at the summit of the Garth, within the county's northern boundary. Four Iron Age hill fort and enclosure sites have been identified within Cardiff's county boundaries, including Caerau Hillfort, an enclosed area of 5.1 hectares (12+1⁄2 acres). …