What did rulers do in attempts to aid each other in case of revolution?

Offer military aid, such as expeditionary troops, and in case of the country being unsafe, a flight to theirs.

the two things that develop a strong social foundation are: a. separation of church and states e. education received attention separation of church and states separate the illogical  argument that came from religious beliefs to a fact based belief. while education will make us remember the past to avoid the repeat of our mistakes.