What are some lessons we can learn from history?

Here's one: Sometimes the bros are loyal.

If you are a powerful monarch, you can have a powerful and competent second-in-command, and they won't necessarily try to revolt or usurp you.

• Augustus and Agrippa
• Justinian and Belisarius
• Genghis Khan and Subutai

Augustus, Justinian, and Genghis Khan all had talented underlings with lots of autonomy and they didn't revolt or try to stage a coup.

Now it's extremely dangerous to throw a coup, so it's not just tenderness and gratitude that kept them loyal. But it's good to know that it's not necessarily suicidal to give competent underlings power and autonomy.