Answer :
To protect themselves against the invasions of Napoleon Bonaparte, nations living under the Ancient Regime employed various strategies. Some of the ways they safeguarded themselves included:
1. **Forming Coalitions**: Countries such as Austria, Prussia, Russia, and Britain joined forces in coalitions to collectively resist Napoleon's advances. By uniting their military strength, they aimed to counter Napoleon's expansionist ambitions.
2. **Guerrilla Warfare**: In regions occupied by French forces, local populations organized guerrilla warfare tactics to disrupt and resist Napoleon's troops. These irregular tactics aimed to wear down the enemy and make occupation difficult.
3. **Scorched Earth Policy**: In some instances, nations adopted a scorched earth policy where they destroyed crops, resources, and infrastructure to deny Napoleon's army vital supplies. This strategy aimed to weaken the enemy's logistical capabilities and reduce their ability to sustain a long campaign.
4. **Fortifications and Defense**: Nations invested in fortifying key cities and regions to withstand sieges and attacks from Napoleon's forces. Strong defensive positions helped in resisting and repelling enemy incursions.
5. **Diplomacy**: Through diplomatic efforts, nations sought to form alliances, negotiate peace treaties, and engage in diplomatic maneuvers to counter Napoleon's influence and expansion. Diplomatic efforts aimed to isolate Napoleon and weaken his political and military alliances.
By employing a combination of military, diplomatic, and strategic tactics, nations under the Ancient Regime sought to protect themselves against the advances of Napoleon Bonaparte and maintain their sovereignty and independence.