Tiberius asked the Senate to decree Castor Protector of the People, which was as much as pointing him out as heir to the monarchy. This request caused general relief. It was taken as a sign that Tiberius was aware of Sejanus' ambitions and intended to check them. When the decree was passed someone proposed that it should be printed on the walls of the House in letters of gold. Nobody realised that it was at Sejanus' own suggestion that Castor was so honoured; he had hinted to Tiberius that Castor, Agrippina, Livia and Gallus were in league together and proposed this as the best way to see who else belonged to their party. It was a friend of his own who had made the proposal about the gold inscription, and the names of senators who supported this extravagant motion were carefully noted.
Castor was more popular now among the better citizens than he had been. He had given up his drunken habits--the death of Germanicus seemed to have sobered him--and though he still had an inordinate love of bloodshed at sword-fights and dressed extravagantly and betted enormous sums on the chariot races, he was a conscientious magistrate and a loyal friend. I had little to do with him, but when we met he treated me with far greater consideration than before Germanicus'
death.
The bitter hatred between him and Sejanus always threatened to blaze up into a quarrel, but Sejanus was careful not to provoke Castor until the quarrel could be turned to account. The time had now come. Sejanus went to the Palace to congratulate Castor on his protectorship and found him in his study with Livilla.
There were no slaves or freedmen present, so Sejanus could say what he pleased.
By this time Livilla was so much in love with him that he could count on her to betray Castor as she had once betrayed Postumus--somehow he knew that story--and there had even been talk between them in which they had regretted that they were not Emperor and Empress, to do as they pleased. Sejanus said, "Well, Castor, I've worked it for you all right! Congratulations!"
Castor scowled. He was only "Castor" to a few intimates. He had won the name, as I think I have explained, because of his resemblance to a well-known gladiator, but it had stuck because one day he had lost his temper in an argument with a knight. The knight had told him bluntly at a banquet that he was drunk and incapable, and Castor, shouting "Drunk and incapable, am I? I'll show you if I'm drunk and incapable," staggered from his couch and hit the knight such a terrific blow in the belly that he vomited up the whole meal. Castor now said to Sejanus:
"I don't allow anyone to address me by a nickname except a friend or an equal, and you're neither. To you I'm Tiberius Drusus Caesar. And I don't know what you claim to have 'worked' for me. And I don't want your congratulations on it, whatever it is. So get out."
Livilla said: "If you ask me, I call it pretty cowardly of you to insult Sejanus like this, not to mention the ingratitude of kicking him out like a dog when he comes to congratulate you on your protectorship. You know that your father would never have given it to you except on Sejanus' recommendation."
Castor said: "You're talking nonsense, Livilla. This filthy spy has had no more to do with the appointment than my eunuch Lygdus. He's just pretending to be important. And tell me, Sejanus, what’s this about cowardice?"
Sejanus said: "Your wife is quite right. You're a coward.
You wouldn't have dared to talk to me like this before I got you appointed Protector and so made your person sacrosanct. You know perfectly well that I'd have thrashed you."
"And serve you right," said Livilla.
Castor looked from one face to the other and said slowly: "So there's something between you two, is there?"
Livilla smiled scornfully: "And suppose there is? Who's the better man?"
Castor shouted: "All right, my girl, we'll see. Just forget for a moment that I'm Protector of the People, Sejanus, and put your fists up."
Sejanus folded his arms.
"Put them up, I say, you coward."
Sejanus said nothing, so Castor struck him hard across the face with his open palm. "Now get out!"
Sejanus went out with an ironical obeisance and Livilla followed him.
This blow settled Castor's fate. The account that Tiberius heard from Sejanus, who came to him with the mark of Castor's slap still red on his cheek, was that Castor had been drunk when Sejanus had congratulated him on his protectorship and had struck him across the face saying: "Yes, it's good to feel that I can do this now without fear of being hit back. And you can tell my father that I'll do the same to every other dirty spy of his." Livilla confirmed this the next day when she came to complain that Castor had beaten her; she said that he had beaten her because she told him how disgusted she was with him for striking a man who could not strike back and for insulting his father. Tiberius believed them. He said nothing to Castor but put up a bronze statue of Sejanus in Pompey's theatre, an extraordinary honour to be paid to any man in his lifetime. This was understood to mean that Castor was out of favour with Tiberius in spite of his protectorship [for Sejanus and Livilla had circulated their version of the quarrel] and that Sejanus was now the one person whose favour was worth courting. Many replicas of the statue were therefore made, which his partisans put in a place of honour in their halls on the right hand of Tiberius' statue: but the statues of Castor were rarely seen. Castor's face showed his resentment so clearly now whenever he met his father that Sejanus' task was made easy. He told Tiberius that Castor was sounding various senators as to their willingness to support him if he usurped the monarchy and that some of them had already promised their help. The ones who seemed most dangerous to Tiberius were therefore arrested on the familiar charge of blaspheming against Augustus. One man was condemned to death for having gone into a privy with a gold coin of Augustus' in his hand. Another was accused of having included a statue of Augustus in a list of furniture for sale in a country villa. He would have been condemned to death if the Consul who was judging the case had not asked Tiberius to give his vote first. Tiberius was ashamed to vote for the death-penalty, so the man was acquitted, but condemned soon after on another charge.
Castor became alarmed and asked Livia for her help against Sejanus. Livia told him not to be afraid: she would soon bring Tiberius to his senses. But she had no confidence in Castor as an ally. She went to Tiberius and told him that Castor had accused Sejanus of debauching Livilla, of abusing his position of confidence by levying blackmail on rich men in Tiberius' name, and of aiming at the monarchy; that he had said that unless Tiberius dismissed the rascal soon he would take the matter into his own hands; and that he had then asked for her co-operation. By putting the case like this to Tiberius she hoped to make him as mistrustful of Sejanus as he was of Castor and thus to cause him to fall back into his old habit of dependence on her.
For a time at least she succeeded. But then an accident suddenly convinced Tiberius that Sejanus was as loyally devoted as he pretended to be and as all his actions had hitherto shown him. They were picnicking together one day with three or four friends in a natural cave by the seashore, when there was a sudden rattle and roar and part of the roof fell in, killing some of the attendants and burying others, and blocking up the entrance. Sejanus crouched with arched back over Tiberius--they were both unhurt--to shield him from a further fall. When the soldiers dug them out an hour later he was found still in the same position.