The year 55 BC saw Julius Caesar landing in Britannia opposed by Celtic warriors and their dogs. This makes the English Mastiff one of the oldest recorded breeds according to Julius Caesar’s description of them in his accounts. Often War Dogs would be sent into battle with large protective spiked metal collars and coats of mail armor. It was also common practice for the Romans to strap buckets of flaming oil to the backs of their War Dogs and send them into the enemy’s front lines to disrupt the opposing cavalry. These canines were called Piriferi, or 'fire bearer'. We can say that Julius Caesar was the inventor of the first K-9 units.