In 197 AD, the armies of Septimius Severus and Clodius Albinus met at Lugdunum, on the site of present day Lyon. If we believe the numbers given in Cassius Dio, this was the greatest and bloodiest clash between two Roman armies in history. 300,000 soldiers were present in total, according to Dio. The numbers are debated, but nevertheless the titanic scale of this clash in ancient history is clear to see. In this episode Tristan speaks to Dr Jonathan Eaton about the lead up to the battle, how Severus and Albinus went from friends to foes, and whether we can really call this the biggest battle in Roman history. Jonathan is Academic Registrar at Teeside University and author of ‘Leading The Roman Army: Soldiers and Emperors 31 BC - 235 AD’.