The six military tribunes of each legion were, indeed, of higher rank, but they were often untested young noblemen, obliged to get a certain “military experience” before returning to Rome to sue for seats in the Senate and the favor of the Emperor. The centurions, however, were a permanent body. They had enlisted in the legion, and their whole life was tied up with it. If their methods were harsh, they prided themselves on showing an example of daring yet scientific valor in every battle. They were intensely devoted to their corps, its honor, and the honor of their comrades. With good centurions a motley host of raw recruits soon became formidable legionaries; without them the most skilful general might strive in vain to organize an army. [Illustration: LEGIONARIES (REGULAR TROOPS-OF-THE-LINE): one soldier is carrying his equipment upon a “Marius’s Mule,” a staff arranged to serve as a knapsack, invented by Marius about 110 B.C.] As centurion Quadratus found a straight line of promotion before him. He was obliged to begin as the sixth centurion of the tenth cohort, and by process of seniority he was entitled to rise to first centurion of the first cohort. He was making fair progress but advancement was discouragingly slow, and he might have ended (as did most of his fellow officers) only part way up the ladder before he reached the retiring age, when a great good fortune came to him. While only a private he had won the “civic crown” (_corona civica_) of oak leaves for saving the life of a comrade in battle; he had also gained the golden “mural crown” (_corona muralis_) for being the first in a desperate storming party over the parapet of a crude fortress held by the Germans. But now, while acting as senior centurion of a large detachment, with the commanding tribune absent, he learned that a Roman garrison somewhere in the heart of the Black Forest region was hard pressed by a horde of Chatti. He led up his men suddenly and skilfully, broke through and dispersed the Barbarians and saved the garrison when it was at last gasp. For this he was awarded the “siege crown” (_corona obsidionalis_), a remarkable honor given by the rescued garrison, and plaited out of grass and weeds plucked on the spot of battle,[168] to the leader who had saved them.