‘To-night, if you will,’ answered Nero, ‘but it must be secret. There must be no scandal. A story must be trumped up. The Augusta must be deceived. Octavia must be deceived. None of his adherents must know of it, unless they can be trusted to hold their tongues.’
‘Nearly all the people about him are in our pay,’ said Tigellinus. ‘I think it can be done.’
That night no soldier was on guard near the room of Britannicus, and Titus regarded this as a fatal sign. When he received from Onesimus the intelligence which Acte had given him, he said that he would draw his own bed across the door of the Prince’s room inside, so that none could enter without his knowledge. He asked Onesimus to keep watch in concealment outside, and make a noise if any one should approach.
‘I can imitate exactly the bark of the Empress’s lap-dog,’ said Onesimus, ‘for Aponia, who has charge of it, often lets me tease it. If I make this noise in the quiet of the night it is sure to set other dogs barking, and then I will spring out of my hiding-place as if the sound had awoke me.’
Proud of the confidence reposed in him, proud to be the guard of a Cæsar’s life, Onesimus put on a black lacerna, shrouded himself in a dark corner, hidden behind the shield of an Amazon. The Palace sank to deep silence, broken only by the faint, distant tramp of the sentinel who kept watch outside the passage which led to the cubiculum of the Emperor.
About an hour after midnight he heard a stealthy footstep approaching, and saw the occasional gleam of a lantern which was hidden under the cloak of the murderer. Breathless with anxiety, he watched and listened. The slave came near to the room of Britannicus. Noiselessly he placed his lantern on the floor, then he drew a large dagger, and Onesimus saw its blade flash in the light as the wretch examined it. One instant more and his hand was thrusting an oiled key into the lock.
Then it was that Onesimus gave a short, sharp sound like the bark of a pet dog. The murderer started violently. Onesimus repeated the sound, which was immediately taken up by a dog which belonged to one of the freedwomen. Hesitating no longer, he leapt out of his shelter with the challenge, ‘Who goes there?’ and at the same moment Titus, who had slept in his clothes, unfastened the door, and sprang in front of it with a sword in his hand.
Without staying an instant longer the murderer dashed down his lantern and fled, for slaves and freedmen were heard stirring on every side. Onesimus did not attempt to pursue him, but quietly slipped back to his own cell. He knew that for that night the dark plot was frustrated and Britannicus was safe.
To the slaves whom the noise had disturbed Titus only said that he had been troubled by the nightmare, and bade them return to sleep. But not a few of them shrewdly suspected that they had not been told the whole truth.