When the city is used to living under a Prince but the line is extinguished, [the citizens] are used to obeying on the one hand, and on the other hand, their old Prince is gone. They can neither agree among themselves nor can they live in freedom. This makes them likely to take arms; a new Prince can more easily take over and secure his reign.

In Republics, there is more life, more hate, more desire for revenge. You can’t leave them alone and you can’t allow the memory of the old liberty. The safest way to deal with them is ruin them and then live there.