The earliest historians give a Celtic or Gallic origin to the Bastarnae. Roman historian Livy, writing in c. 10 AD, attests that the Bastarnae spoke Celtic. Relating the Bastarnic invasion of the Balkans of 179 BC (see Allies of Philip of Macedon below), he describes them then as "they were not very different in either language or manners" to the Celtic tribe of the Scordisci, a tribe of Pannonia. The Scordisci are described as Celtic by Strabo (although he adds that they had mingled with Illyrians and Thracians). The Greek historian Plutarch inform us that the Roman consul Hostilius "secretly stirred up the Gauls settled along the Danube, who are called Basternae".