At this juncture, the Roman empire was convulsed by its first major civil war for a century, the Year of the Four Emperors. The cause was the fall of the Julio-Claudian dynasty. The descendants of Augustus had enjoyed the automatic and fervent loyalty of ordinary legionaries in the frontier armies. But Galba possessed no such legitimacy in their eyes. Supreme power was now open to whichever general was strong enough to seize it (and keep it). First, in AD 69, Galba's deputy, Otho, carried out a coup d'état in Rome against his leader, who was killed by the Praetorian Guard.