The Celtic peoples were a linguistic-cultural group in Europe around 2800BCE. The history of the Celts is a subject of controversy in part because the Celts weren’t too keen on keeping a lot of written records but also due to subjugation from various imperial powers, namely the Roman Empire. Few scholars can agree on what metric to use to decide who was and wasn’t Celtic. The most common defining factor is use of Celtic languages. From here Celts are generally subdivided into one of two groupings either P-Celtic vs Q-Celtic or insular vs continental Celts.