Answer:
to back up each other in the event of war
Explanation:
France and Russia had monarchies with good diplomacy sharing a desire to keep the status quo in European geopolitical landscape.
The Franco-Prussian War left some bitter feelings.
In case of war France agreed to protect Russia , Russia then also would put pressure limiting Austria in East Europe. They foresaw Germany and Austria intentions on expanding Central Europe.
They decide to form the Dual Alliance, a political and military pact between France and Russia handled in secret first in 1894.
The Dual Alliance became one of the basic European alliances before WW1.
By 1914, Europe majors powers would lie legally bound to speak for their allies.
France and Russia with Britain became the Triple Entente.
