Mainila incident escalates the Soviet-Finnish crisis

The invasion began the European war. The Soviet-German pact’s secret arrangements shaped the partition of Polish territory, while civilians faced invasion, occupation, and displacement.

Soviet forces crossed the Polish border as the Polish state faced German invasion. Soviet authorities described the move as protecting Ukrainians and Belarusians, while it also extended Soviet control...

The treaty revised the division of occupied Polish territory and formalized spheres of influence. Its confidential protocols show how great-power bargaining over borders overrode the sovereignty of...

The agreement granted the USSR military bases in Latvia. Officially framed as mutual assistance, it constrained Latvian sovereignty and foreshadowed further Soviet pressure on the Baltic states.

The treaty transferred Vilnius to Lithuania but required Soviet military bases on Lithuanian territory. It combined a territorial concession with a powerful strategic foothold that compromised...

Soviet forces crossed into Finland after negotiations over border security and territorial concessions failed. The invasion was an act of aggression that produced heavy civilian and military losses...

The League condemned the Soviet invasion of Finland and expelled the USSR. The decision exposed the weakness of collective security and the limits of Soviet claims to defend peace through...

Soviet forces entered Estonia and Latvia after ultimatums and entered Lithuania under a similar demand. The occupation followed the 1939 mutual-assistance pacts; subsequent controlled political...

Following a Soviet ultimatum, Romania withdrew and Soviet troops entered Bessarabia and Northern Bukovina. The move expanded Soviet control and affected Romanian, Ukrainian, Jewish, Russian, and other...

Newly installed assemblies adopted resolutions seeking incorporation. These votes followed Soviet military occupation and political coercion; the Soviet and Baltic accounts of the process remain...