The Praetorian Guard had rarely fought in field battles, so Julianus marched them into the Campus Martius and drilled the guard in the construction of fortifications and field works. Despite this training, the Praetorian Guard was still undertrained compared to the field legionaries of Severus. Severus first secured the support of Albinus, declaring him Caesar, and then seized Ravenna and its fleet. Severus killed Tullius Crispinus, the Praetorian prefect, who was sent to negotiate with Severus and slow his march on Rome and won over to his cause the ambassadors sent to turn his troops.