Library of Congress
A cartoon by Puck magazine celebrating the "resumption" of diplomatic relations between Greece and Persia in 1902, interrupted after the outbreak of the Greco-Persian Wars in 490 BC.
Of course, these "extended wars" have never actually had any bearing on international relations.
Instead, the ongoing de facto peace overrode any technicalities on the world stage. However, the patching up of these diplomatic irregularities has been used by countries still technically at war to boost their current ties and gain media attention.
We have listed nine such examples of extended wars below.