 It is hypothesised that it was initially a celtiberian castro (fortress) that dominated the basin located north of the city, with the defensive advantage of the Cigüela river which served as a moat.Remains of the fortress have not appeared, but a ceramics fragment from 5th century BC Attica provides testimony of the area being populated that much earlier.The first recorded mention of Segóbriga is a brief reference by Greek geographer Strabo, stating that Quintus Caecilius Metellus Pius fought in the Wars of Sertorius, in the Celtiberian region around Bílbilis and Segóbriga.