'"No, Caesar," said he. "Do not tempt the Gods too far. Take men, or engines, but not both; else we refuse."' 'Engines?' said Una. 'The catapults of the Wall--huge things forty feet high to the head--firing nets of raw stone or forged bolts. Nothing can stand against them. He left us our catapults at last, but he took a Caesar's half of our men without pity. We were a shell when he rolled up the lists! '"Hail, Caesar! We, about to die, salute you!" said Pertinax, laughing. "If any enemy even leans against the Wall now, it will tumble." '"Give me the three years Allo spoke of," he answered, "and you shall have twenty thousand men of your own choosing up here. But now it is a gamble--a game played against the Gods, and the stakes are Britain, Gaul, and perhaps Rome. You play on my side?" '"We will play, Caesar," I said, for I had never met a man like this man. '"Good. Tomorrow," said he, "I proclaim you Captains of the Wall before the troops." 'So we went into the moonlight, where they were cleaning the ground after the Games. We saw great Roma Dea atop of the Wall, the frost on her helmet, and her spear pointed towards the North Star. We saw the twinkle of night-fires all along the guard towers, and the line of the black catapults growing smaller and smaller in the distance. All these things we knew till we were weary; but that night they seemed very strange to us, because the next day we knew we were to be their masters. 'The men took the news well; but when Maximus went away with half our strength, and we had to spread ourselves into the emptied towers, and the townspeople complained that trade would be ruined, and the autumn gales blew--it was dark days for us two. Here Pertinax was more than my right hand. Being born and bred among the great country-houses in Gaul, he knew the proper words to address to all--from Roman-born Centurions to those dogs of the Third--the Libyans. And he spoke to each as though that man were as high-minded as himself. Now _I_ saw so strongly what things were needed to be done, that I forgot things are only accomplished by means of men. That was a mistake. 'I feared nothing from the Picts, at least for that year, but Allo warned me that the Winged Hats would soon come in from the sea at each end of the Wall to prove to the Picts how weak we were. So I made ready in haste, and none too soon. I shifted our best men to the ends of the Wall, and set up screened catapults by the beach. The Winged Hats would drive in before the snow-squalls--ten or twenty boats at a time--on Segedunum or Ituna, according as the wind blew.