Archaeologists revealed 5th century fortress in Spain by using LIDAR

Led by Spanish archaeologists, a fifth-century fortress surrounded by a substantial defensive wall has been found, according to a new study.

As reported, what was once believed to be an Iron Age hillfort in northwest Spain debouched an early medieval stronghold constructed in the fifth century A.D. Archaeologists used laser scans to determine it.

Archaeologists in northwest Spain were able to locate the fortress on a hilltop thanks to LIDAR (light detection and ranging). An early medieval fortress covering about 25 acres (10 hectares) was discovered using this technique, which bounces hundreds of thousands of laser pulses off the ground from an aircraft flying overhead. The fortress had 30 towers and a defensive wall about 1.2 kilometers long and had 30 towers, as per Live Science.

From archaeologists' point of view, the fortress was built in the first half of the fifth century A.D., possibly on top of an earlier Iron Age hilltop fort, to defend against Germanic invaders after Roman control of the region had collapsed.

It was also a Celtic settlement

Fernández-Pereiro and José Carlos Sánchez-Pardo, a USC archaeologist and the study's co-author, initially believed Castro Valente to be a fortified Celtic settlement when they first started exploring the site.

They quickly discovered proof that the structure was much larger than they had anticipated and that some of its components had been constructed using techniques not standard in the Iron Age. Fernández-Pereiro stated that the archaeological digs "continued to give data that direct us towards a time of post-Roman habitation, possibly in the first part of the 5th century," as per LiveScience.

The fortress's design, building materials, and pottery shards indicate that it was built after the Roman Empire lost control of the area in the early fifth century A.D. when Germanic invaders swept over Spain.

But some 200 years later, the stronghold appears to have been abandoned, perhaps because it was no longer required, according to Fernández-Pereiro. Future studies might shed more light on it and help safeguard it against construction projects like wind farms and forest roads. As the research develops, the team intends to post regular updates on their Facebook page, CastelosnoAire. 

The study was published on December 13.

Study abstract:

El estudio del fenómeno de la forticación posromana está surgiendo con interés para el territorio de la antigua provincia romana de Gallaecia. En los últimos años se han realizado importantes progresos en la localización y estudio de estos yacimientos encuadraos en la transición del estado romano a la Alta Edad Media. La combinación de técnicas no invasivas con la excavación arqueológica permite ampliar la información relativa a estos recintos for tificados. En el presente texto se presenta una revisión del proceso metodológico de estudio del yacimiento de Castro Valente (Padrón, Galicia).