The Castro culture ('Culture of the Castles') developed during the Iron Age, and flourished during the second half of the first millennium BC. It is usually considered a local evolution of the Atlantic Bronze Age, with later developments and influences and overlapping into the Roman era. Geographically, it corresponds to the people Roman called Gallaeci, which were composed by a large series of nations or tribes, among them the Artabri, Bracari, Limici, Celtici, Albiones and Lemavi. They were capable fighters: Strabo described them as the most difficult foes the Romans encountered in conquering Lusitania, while Appian mentions their warlike spirit, noting that the women bore their weapons side by side with their men, frequently preferring death to captivity. According to Pomponius Mela all the inhabitants of the coastal areas were Celtic people.

What does the Castro culture's name mean?