A mercenary who saved Siena was killed for it anyway, while Bismarck built his career by propping up a weak king on purpose, to argue that being needed is safety and being merely useful is not.
A mercenary soldier saves a city. Siena, under attack, about to fall — and then it doesn't, because of one man. Now the city has a problem: how do you pay him back?
Money doesn't cover it. Titles don't either. Somebody floats the idea of making him Lord of the City, and even that feels too small. So they call an assembly. They debate it properly, because this isn't a small decision. And in the middle of the debate, a man stands up and says the quiet part out loud: kill him. Then name him a saint. Then worship him.
That is what they did.
Not far away, a few decades later, the same arithmetic runs again on a different man. The Count of Carmagnola was a condottiero — a mercenary captain, brave, successful, the kind of soldier cities fight wars with. In 1442 he was working for Venice, at war with Florence at the time. Venice calls him back. Being the people's favourite gets him everything — luxury, love, respect, and that evening, an invitation to dine with the Duke himself, inside the palace.
The Duke's guards come to walk him there. Partway through the city he notices they've taken a different route than usual. They cross the famous Bridge of Sighs, and only then does he work out where he's actually being taken — down, into the cells underneath. The next morning they bring fabricated charges against him and bring him out in front of Piazza San Marco. Before the crowd has even understood what's happening, his head is off his shoulders.
Two stories, one detail in common: both men were mercenaries. And mercenaries can be replaced. No matter how great the deed, no city or kingdom builds itself around a single soldier — so when that soldier becomes inconvenient, he goes. That's what happens when you're useful but not needed. It got both of them killed.
Here's the law, stated plainly. Law 11 of the 48 Laws of Power: learn to keep people dependent on you. For your own security, make sure people need you for their happiness and their success. Do that and you have nothing to fear from them — whether they outrank you or report to you. And never, ever teach someone so completely that they stop needing you to do it.
Plenty of soldiers through history found themselves exactly where the men of Siena and Carmagnola did. They won battles for their kingdom, for their people — and were imprisoned or executed anyway. Because soldiers are replaceable. One soldier dying doesn't move the needle. I'm talking about individuals here, not whole armies. When you can recruit a replacement cheap, the original was never worth that much to begin with. Carmagnola thought his fame made him free. What he never worked out was that what he actually needed was to make himself more necessary, not more celebrated. Get good enough at what you do that whoever you're doing it for cannot let you go. Your work has to matter enough that you decide when it ends, not them — or you'll end up crossing your own Bridge of Sighs one day.
Now look at someone who ran the opposite play and won.
1847. Otto von Bismarck becomes a deputy in the Prussian parliament. He's 32, with no friends and no allies worth naming. Rather than scrambling to pick a side — the liberals, a particular minister, even public opinion — he does something that looks like a mistake. He attaches himself to Frederick William IV, King of Prussia, at the exact moment the king is at his weakest: indecisive, bending to every liberal demand, a man Bismarck privately couldn't stand. And then Bismarck advises him anyway. Day and night. Props him up, steadies him, pushes back on his ego hard enough that the king actually becomes fit to rule, and slowly rebuilds his power until Prussia is the strongest force it's been in years.
Frederick dies in 1861. His brother William takes the throne and wants nothing to do with Bismarck — doesn't like him, doesn't want him close. Doesn't matter. Within a short time William finds himself surrounded by the same enemies his brother had, his own position shaking under him. And Bismarck is right there again, loyal, holding him up, handing him exactly the strength he needs. Day by day William gets more dependent, until he makes Bismarck his Prime Minister. They argue constantly, over policy, over decisions — but Bismarck knows precisely what he's worth. When things start slipping, he threatens to resign. William can't let that happen, so William does what Bismarck wants. The king makes the decisions. Bismarck writes them. He was the real hand on the lever. A few years later Bismarck's maneuvering pulls the German states together, and he's the one who tells William to take the title Emperor of Germany. No one objects. In the eyes of the world, William is becoming the most powerful man in Europe. In the room, it's Bismarck gaining the power — the new Imperial Chancellor running the new Emperor from the shadows.
Most ambitious people chase power by attaching themselves to whoever already has it. The logic feels obvious: join a strong group, become strong by association. Bismarck thought the opposite. He knew that joining a powerful camp meant he'd never matter inside it — they'd use him until he wasn't useful anymore, then put him out. So he backed the king instead, weak as the king was. If you're smart, hitching yourself to a weak master can be the better move, because it's how you build the dependency instead of just borrowing someone else's. Be their strength, and their strength becomes yours. Just make sure you're the foundation it's standing on — important enough that if you go down, the whole structure goes with you. That's the only version of this where the power is actually yours to use.
Dependency doesn't only come from being useful. Sometimes it comes from someone else's weakness, and nobody ran this better than Louis XI of France — the Spider King. His weakness was astrology. He kept a personal astrologer at court and believed every word out of the man's mouth. One day the astrologer predicts a woman at court will die within eight days. She does. Louis panics. Either the astrologer arranged it to prove himself right, or he genuinely sees the future — and either way, intentionally or not, that astrologer now has power over the king. Both possibilities end the same way in Louis's head: the astrologer has to die.
One evening Louis calls him up to a high room in his castle. Before the man arrives, Louis tells his guards: on my signal, pick him up and throw him out the window. The astrologer walks in. Before Louis gives any signal, he asks him one question — you can supposedly read fate, so tell me: what happens to you? How long do you have?
The astrologer answers: strange game the stars play, my lord — my death will come exactly three days before yours.
Louis never gives the signal. From that day on, the king looks after that astrologer personally, gives him whatever he wants. The man read the room, understood exactly where the power sat, and made that power bend to him instead. Because from that moment, the king's life was dependent on him.
The largest power you can hold is getting people to do what you want. If you can manage that without hurting anyone, better still — and the way there is dependency. Understand what people need. Until someone is dependent on you, you cannot use them. Skip that step and the dependency runs the other way: you get used, then discarded. No better than a transaction that ends the moment it's paid for.
Some of you are reading this thinking, I don't need anyone, I'm self-sufficient, that's my strength. It isn't. It's a mistake. Power is a social game, and social games need other people in them — friends, allies, and yes, a few enemies too. Treating dependency as only a weakness is where people get this wrong, because dependency cuts both directions. If someone depends on you, you are — indirectly — now dependent on them too. And some situations will put you on the other end of that leash, dependent on someone else outright. Both run on the same rule: control. If someone needs you, keep the control. If you need someone, still try to keep the control. Power that can't be controlled isn't power, it's just exposure.
There's only one lever that gets you that control: necessity. The world runs on it. People don't move until they feel a need. So be the need — especially for the people above you — and they stay tied to you. Necessity works because it triggers something stronger than respect or affection: fear. The more they need you, the more afraid they are of losing you, and fear is an emotion you can run even from underneath someone, the way Bismarck ran it from inside a palace that technically belonged to someone else.
It genuinely doesn't matter whether the person on the other end of this likes you, dislikes you, loves you or can't stand you. As long as the need is alive, the relationship is alive. The day the need ends, so does the relationship — and whatever was built on top of it goes down with it. This is running quietly right now in places nobody's named it: the colleague nobody can onboard a replacement for, the parent still doing a grown child's laundry, the partner who handles everything so the other one never learns how. Some of that is comfort. Some of it is a cage built one favour at a time — and the person who built it can't walk away from it either, because leaving means someone finds out they were never actually needed.
Which leaves you with the uncomfortable half of this law, the half the book never quite spells out: if you cannot make yourself needed in this world, the world does not need you either.
Law 11 of Robert Greene's The 48 Laws of Power.