The pugio was a small dagger used by Roman soldiers as a sidearm. It seems likely that the pugio was intended as an auxiliary or backup weapon, but it found many uses, especially as a utility knife. Officials of the empire took to wearing ornate daggers in the performance of their offices, and some would wear concealed daggers as a defense against contingencies. The dagger was a common weapon of assassination and suicide; for example, the conspirators who stabbed Julius Caesar used pugiones.
According to the Latin dictionaries, such as Lewis & Short, the term first appears in the late republican author, Marcus Tullius Cicero, with reference to the dagger used by Marcus Brutus to stab Julius Caesar. Suetonius confirms that all the conspirators used the pugio on that occasion and some later killed themselves with it. In the pages of Cicero the pugio appears to have been the favored weapon of high-ranking assassination and suicide because it was so easily concealed in the folds of flowing Roman garments.
Throughout the period the outline of the hilt remained essentially the same. It was made with two layers of horn or wood sandwiching the tang, each overlaid with a thin metal plate. Occasionally the hilt was decorated with engraving or inlay. Note that the hilt is 10 cm to 13 cm (4 in - 5 in) long overall and that the grip is quite narrow; it will always seem to be too small.
References to the pugio are more common in the literature of the empire, especially in Tacitus and Suetonius. Tacitus reports that Gnaeus Domitius Corbulo had a soldier executed for not wearing a sword while digging a trench and another for wearing only a pugio in the same activity, from which it can be deduced that all soldiers wore them.
The pugio became an ornate sidearm of officers and dignitaries as well, a custom reminiscent of the daggers after which the Saxons were named. These Germanic mercenaries served in the Roman army. The emperors came to wear a dagger to symbolize the power of life and death. The emperor, Vitellius, attempts to resign his position and offers his dagger to the consul, but it is refused and Vitellius is forced to stay by popular acclaim and the Praetorian guard. Tacitus also relates that a centurion, Sempronius Densus, of the Praetorian guard drew a dagger to save Lucius Calpurnius Piso Licinianus momentarily.
In modern times, the Italian dictator, Benito Mussolini, attempted to recapture the spirit of the Roman military by instituting the dagger salute, a double line of soldiers crossing daggers over the head of the dignitary passing beneath them.