The manager had long since realized that he was dealing with a Belt man, not an Earth citizen, and that the registration robot had sent him the card because of that, not because there was anything illegal. Men from the Belt did not come to Earth either willingly or often.
Still unable to override his instincts—which erroneously told him that there was something "wrong"—the manager said: "What does the 'Sir' mean?"
Harry Morgan glowed warmly. "Well, now, Mr. Manager, I will tell you. I will give you an analogy. In the time of the Roman Republic, twenty-one centuries or so ago, the leader of an Army was given the title Imperator. But that title could not be conferred upon him by the Senate of Rome nor by anyone else in power. No man could call himself Imperator until his own soldiers, the men under him, had publicly acclaimed him as such. If, voluntarily, his own men shouted 'Ave, Imperator!' at a public gathering, then the man could claim the title. Later the title degenerated—" He stopped.
The manager was staring at him with uncomprehending eyes, and Morgan's outward smile became genuine. "Sorry," he said condescendingly. "I forgot that history is not a popular subject in the Welfare World." Morgan had forgotten no such thing, but he went right on. "What I meant to say was that the spacemen of the Belt Cities have voluntarily agreed among themselves to call me 'sir'. Whether that is a title of ability or a title of courtesy, you can argue about with me at another time. Right now, I want my room key."
Under the regulations, the manager knew there was nothing else he could do. He had made a mistake, and he knew that he had. If he had only taken the trouble to read the rest of the card—
"Awfully sorry, Mr. Morgan," he said with a lopsided smile that didn't even look genuine. "The—"
"Watch those courtesy titles," Morgan reprimanded gently. "'Mister' comes ultimately from the Latin magister, meaning 'master' or 'teacher'. And while I may be your master, I wouldn't dare think I could teach you anything."
"All citizens are entitled to be called 'Mister'," the manager said with a puzzled look. He pushed a room key across the desk.
"Which just goes to show you," said Harry Morgan, picking up the key.