The timeline of Cardiff history shows the significant events in the history of Cardiff which transformed it from a small Roman fort into the modern capital city of Wales. The word 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 in effect a form of Taf (Taff), the river which flows by Cardiff Castle.